Aerogel-based components and systems for electric vehicle thermal management

ABSTRACT

Aerogel-based components and systems for electric vehicle thermal management are provided. Exemplary embodiments include a heat control member. The heat control member can include reinforced aerogel compositions that are durable and easy to handle, have favorable performance for use as heat control members and thermal barriers for batteries, have favorable insulation properties, and have favorable reaction to fire, combustion and flame-resistance properties. Also provided are methods of preparing or manufacturing such reinforced aerogel compositions. In certain embodiments, the composition has a silica-based aerogel framework reinforced with a fiber and including one or more opacifying additives.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit of priorityunder U.S.C. § 120 to U.S. Pat. Application Serial No. 17/106,940, filedon Nov. 30, 2020, which claims the benefit of priority from U.S.Provisional Pat. Application No. 62/942,495, filed Dec. 2, 2019, U.S.Provisional Pat. Application No. 62/958,135 filed Jan. 7, 2020, and U.S.Provisional Pat. Application No. 63/056,527 filed Jul. 24, 2020, each ofwhich is hereby incorporated by refence in its entirety, with anydefinitions of terms in the present application controlling.

FIELD OF THE INVENTION

The invention relates, generally, to aerogel technology. Morespecifically, the present disclosure relates to heat control membersincluding aerogel technology. In particular embodiments, the presentdisclosure relates to high performance heat control members includingaerogel technology for separating battery cells or insulating batterycomponents.

BACKGROUND OF THE INVENTION

Low-density aerogel materials are widely considered to be the best solidinsulators available. Aerogels function as insulators primarily byminimizing conduction (low structural density results in tortuous pathfor energy transfer through the solid framework), convection (large porevolumes and very small pore sizes result in minimal convection), andradiation (with IR absorbing or scattering dopants). Aerogels can beused in a broad range of applications, including heating and coolinginsulation, acoustics insulation, electronic dielectrics, aerospace,energy storage and production, and filtration. Furthermore, aerogelmaterials display many other interesting acoustic, optical, mechanical,and chemical properties that make them abundantly useful in variousinsulation and non-insulation applications.

Thermal insulation suitable for reliably controlling heat flow fromheat-generating parts in small spaces and to provide safety andprevention of fire propagation for such products are needed in thefields of electronic, industrial and automotive technologies. Thermalinsulation sheets with superior properties in compression may be usefulin addressing these needs, for example as separators in lithium ionbattery modules.

The safety standards for lithium ion batteries include a fire exposuretest. The fire exposure test is a test method in which a cell in abattery module is allowed to undergo thermal runaway and then it isdetermined whether ignition or rupture occurs as a result of thermalpropagation to other cells including the adjacent cell. A safety designintended to block propagation of thermal runaway to the adjacent celltypically involves inclusion of a material superior in thermalinsulation properties between cells.

Conventional types of insulation, such as foam or fiber sheets, cantolerate high temperatures, but have a relatively low capacity forinsulation or thermal containment. For such materials, the thickness ofthe insulation must be increased in order to provide effective thermalmanagement. However, the space requirements for battery modules limitthe size of the module, as well as the space between cells within themodule. Similarly, it is desirable to limit the overall weight of thebattery module. Thus, resistance to heat propagation and firepropagation need to be achieved while minimizing the thickness andweight of materials used to provide the necessary thermal properties. Adifferent type of insulation system, material, and method to provideeffective insulation, thermal containment and fire propagationprotection is needed.

Aerogel materials are known to possess about two to six times thethermal resistance of other common types of insulation, e.g., foams,fiberglass, etc. Aerogels can increase effective shielding and thermalinsulation without substantially increasing the thickness of theinsulation or adding additional weight. Aerogels are known to be a classof structures having low density, open cell structures, large surfaceareas, and nanometer scale pore sizes.

U.S. Pat. Publication No. 2012/0142802 of Steinke discloses open-cellfoams filled with particles of aerogel. U.S. Pat. Publication No.2019/0161909 of Oikawa discloses a thermal insulation sheet including anon-woven fabric and an aerogel. However, these documents do notdisclose materials that have the desired thermal, fire, mechanical andhydrophobic properties and the combination of many desired propertiesfor use in heat control members or thermal barriers for separatingbattery cells or the methods for producing such materials.

It would be desirable to provide reinforced aerogel compositions withimproved performance in various aspects, including in compressibility,compressional resilience, compliance, thermal resistance,hydrophobicity, fire reaction and others, individually and in one ormore combinations. In view of the art considered as a whole at the timethe present invention was made it was not obvious to those of ordinaryskill in the field of this invention how the shortcomings of the priorart could be overcome.

While certain aspects of conventional technologies have been discussedto facilitate disclosure of the invention. Applicants in no way disclaimthese technical aspects, and it is contemplated that the claimedinvention may encompass one or more of the conventional technicalaspects discussed herein.

The present invention may address one or more of the problems anddeficiencies of the prior art. However, it is contemplated that theinvention may prove useful in addressing other problems and deficienciesin a number of technical areas. Therefore, the claimed invention shouldnot necessarily be construed as limited to addressing any of theparticular problems or deficiencies discussed herein.

In this specification, where a document, act or item of knowledge isreferred to or discussed, this reference or discussion is not anadmission that the document, act or item of knowledge or any combinationthereof was at the priority date, publicly available, known to thepublic, part of common general knowledge, or otherwise constitutes priorart under the applicable statutory provisions; or is known to berelevant to an attempt to solve any problem with which thisspecification is concerned.

SUMMARY OF THE INVENTION

The long-standing but heretofore unfulfilled need for improved aerogelcompositions is now met by a new, useful, and nonobvious invention.

In one general aspect, the present disclosure provides aerogelcompositions, e.g., reinforced aerogel compositions, that are durableand easy to handle, which have favorable resistance to heat propagationand fire propagation while minimizing thickness and weight of materialsused, and that also have favorable properties for compressibility,compressional resilience, and compliance. In another general aspect, thepresent disclosure provides heat control members that include an aerogelcomposition, a reinforced aerogel composition, or combinations thereof.For example, a heat control member according to aspects disclosed hereincan include at least one layer of an aerogel composition or reinforcedaerogel composition. For another example, a heat control memberaccording to aspects disclosed herein can include a plurality of layersof an aerogel composition or reinforced aerogel composition.

In an exemplary aspect, the present disclosure provides a heat controlmember including an aerogel composition. In certain embodiments, theheat control member is substantially planar and has a first major outersurface and a second major outer surface. In exemplary embodiments, theaerogel composition includes one or more additives. The additives can,in some embodiments, be present at a level of about 5 to 20 percent byweight of the aerogel composition. The additives can, in someembodiments, be present at a level of about 10 to 20 percent by weightof the aerogel composition. In certain embodiments, the heat controlmember has a thermal conductivity of less than about 40 mW/mK. Inexemplary embodiments, the heat control member includes a plurality oflayers of the aerogel composition.

In another exemplary aspect, the present disclosure provides a heatcontrol member including at least one layer of an aerogel composition,at least one compliant member, and a thermally capacitive material. Theaerogel composition includes one or more additives, the additives beingpresent at a level of at least about 5 to 20 percent by weight of theaerogel composition. The additives can, in some embodiments, be presentat a level of about 10 to 20 percent by weight of the aerogelcomposition. In exemplary embodiments, the heat control member includesa plurality of layers of the aerogel composition. In some embodiments,the thermally capacitive material is disposed between at least twolayers of the aerogel composition. The thermally capacitive material canbe any material having a specific heat capacity of at least about 0.3J/(g-C). In some embodiments, the material providing thermal capacitancehas a specific heat capacity of at least about 0.5 J/(g-C). For example,the thermal capacitive material can include at least one layercomprising metal. In exemplary embodiments, the at least one compliantmember can include a compressible material, i.e., a material that can becompressed to reduce its thickness while providing a desired resistanceto compression. For example, the compliant member can include a materialselected from the group consisting of polyolefins, polyurethanes,phenolics, melamine, cellulose acetate, and polystyrene. The compliantmember can be disposed adjacent to the aerogel composition or thethermally capacitive material. In an exemplary embodiment, the compliantmember is between at least two layers of the aerogel composition. Insome embodiments, the compliant member is disposed between both layersof the aerogel composition and layers of the thermally capacitivematerial.

In some embodiments, the heat control member has a thermal conductivityof less than about 30 mW/mK or less, less than about 25 mW/mK, less thanabout 20 mW/mK, less than about 18 mW/mK, less than about 16 mW/mK, lessthan about 14 mW/mK, less than about 12 mW/mK, less than about 10 mW/mK,less than about 5 mW/mK, or a thermal conductivity in a range betweenany combination of the aforementioned thermal conductivities. Inexemplary embodiments, the one or more additives include fire-classadditives. In exemplary embodiments, the one or more additives includeopacifiers. In some embodiments, the one or more additives include acombination of fire-class additives and opacifers. For example, the oneor more additives can include a clay mineral, e.g., kaolin. For anotherexample, the one or more additives can be selected from the groupconsisting of boron carbide, diatomite, manganese ferrite, MnO, NiO,SnO, Ag20, Bi203, carbon black, graphite, titanium oxide, iron titaniumoxide, aluminum oxide, zirconium silicate, zirconium oxide, iron (II)oxide, iron (III) oxide, manganese dioxide, iron titanium oxide(ilmenite), chromium oxide, silicon carbide, titanium carbide, tungstencarbide, or mixtures thereof. In a preferred embodiment, the one or moreadditives includes silicon carbide.

In exemplary embodiments, when the first major outer surface is exposedto a temperature of 650° C. or above, the heat control member maintainsa temperature of 120 C or below at the second major surface for at leastabout 1 minute. In some embodiments, when the first major outer surfaceis exposed to a temperature of 650° C. or above, the heat control membermaintains a temperature of 75 C or below at the second major outersurface for at least about 30 seconds. In some embodiments, when thefirst major outer surface is exposed to a temperature of 650° C. orabove, the heat control member maintains a temperature of 150 C or belowat the second major outer surface for at least about 90 seconds. In someembodiments, when the first major outer surface is exposed to atemperature of 650° C. or above, the heat control member maintains atemperature of 150 C or below at the second major outer surface for atleast about 90 seconds. In some embodiments, when the first major outersurface is exposed to a temperature of 650° C. or above, the heatcontrol member maintains a temperature of 170 C or below at the secondmajor outer surface for at least about 90 seconds. In some embodiments,when the first major outer surface is exposed to a temperature of 650°C. or above, the heat control member maintains a temperature of 180° C.or below at the second major outer surface for at least about 2 minutesand preferably at least about 4 minutes.

In another embodiment, these heat profiles are achieved when the heatcontrol member is integrated into the electric vehicles systems alongwith other components with various configurations and environments. Forexample, the heat control member can be integrated into system such asbattery systems in which the heat control member and other componentsmay be subjected to ambient pressure, temperature, and compression(including from gasses other than air).

In exemplary embodiments, the aerogel composition has an uncompressedthickness in the range of about 1 mm to about 10 mm. For example, theaerogel composition can have an uncompressed thickness in the range ofabout 1 mm to about 5 mm. For another example, the aerogel compositioncan have an uncompressed thickness of about 2 mm, an uncompressedthickness of about 3 mm, or an uncompressed thickness of about 4 mm.

In certain embodiments, the aerogel composition has a density of about0.60 g/cm³ or less, about 0.50 g/cm³ or less, about 0.40 g/cm³ or less,about 0.30 g/cm³ or less, about 0.25 g/cm³ or less, about 0.20 g/cm³ orless, about 0.18 g/cm³ or less, about 0.16 g/cm³ or less, about 0.14g/cm³ or less, about 0.12 g/cm³ or less, about 0.10 g/cm³ or less, about0.05 g/cm³ or less, about 0.01 g/cm³ or less, or in a range between anytwo of these values. In an exemplary embodiment, the aerogel compositionhas a density less than about 0.3 g/cm³.

In an exemplary aspect, the present disclosure provides a battery moduleincluding a first battery cell, a second battery cell, and a heatcontrol member according to embodiments disclosed herein disposedbetween at least the first battery cell and the second battery cell.

In an exemplary aspect, the present disclosure provides a battery moduleor battery pack including at least one battery cell and a heat controlmember according to embodiments disclosed herein disposed on the batterycell or on the battery module, e.g., on a surface of the at least onebattery cell or on a surface of the battery module. For example, thebattery module or batter pack has an inner surface and outer surface. Incertain embodiments, the heat control member is on the inner surface ofthe battery module or battery pack. In certain embodiments, the heatcontrol member is on an outer surface of the battery module or batterypack.

In exemplary embodiments, the heat control member includes an aerogelcomposition. In some embodiments, the heat control member has an energyabsorbing capability in the range of about 25 J/g to about 225 J/g.

In embodiments of the aspects disclosed herein, the aerogel compositioncan include a reinforcement material. For example, the reinforcementmaterial includes fibers. For example, the reinforcement material can beselected from the group consisting of discrete fibers, woven materials,non-woven materials, needled non-wovens, battings, webs, mats, felts,and combinations thereof. In some embodiments, the reinforcementmaterial includes an open-cell macroporous framework (“OCMF”) material.For example, the OCMF material can include a melamine-based foam or aurethane-based polymer foam. In other embodiments, the reinforcementmaterial can include a combination of fiber and OCMF material.

In embodiments of the aspects disclosed herein, the heat control membercan have an uncompressed thickness in the range of about 2 mm to about10 mm. For example, the heat control member can have an uncompressedthickness of about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm,about 7 mm, about 8 mm, about 9 mm, about 10 mm or in a range betweenany of the aforementioned thicknesses. In exemplary embodiments, theheat control member can have an uncompressed thickness in the range ofabout 2 mm to about 7 mm.

In some embodiments of the aspects disclosed herein, the heat controlmember can further include an encapsulation member forming at least oneof the first or the second outer surface. For example, the aerogelcomposition can include an encapsulation member. The encapsulationmember can include an encapsulation layer or coating surrounding theaerogel composition and/or the heat control member, for example. Theencapsulation member can include at least one vent to allow air to flowin and out of the panel and, in some embodiments, a particulate filterto keep particulate matter within the encapsulation member.

In exemplary embodiments, the aerogel composition of the heat controlmember is hydrophobic. For example, the aerogel composition has a liquidwater uptake of less than about 15 wt%.

In exemplary embodiments, the aerogel of the aerogel compositioncomprises inorganic, organic, or inorganic/organic hybrid materials. Forexample, the aerogel composition is a silica aerogel composition. Incertain embodiments, the aerogel composition includes alkylated silica.

In certain embodiments, the aerogel composition is lofty. For thepurposes of this patent, a lofty aerogel composition is defined as anaerogel composition that shows the properties of bulk and someresilience (with or without full bulk recovery). In certain embodiments,lofty aerogel composition (i) is compressible by at least 50% of itsoriginal or uncompressed thickness, preferably at least 65%, and mostpreferably at least 80%, and (ii) is sufficiently resilient that aftercompression for a few seconds it will return to at least 70% of itsoriginal or uncompressed thickness, preferably at least 75%, and mostpreferably at least 80%.

In some embodiments, the reinforcement material can include areinforcement including a plurality of layers of material. For example,the plurality of layers of material can be bonded together. In exemplaryembodiments, at least one of the plurality of layers can include a firstmaterial and at least one other layer of the plurality of layers caninclude a second material. The first material and the second materialcan have the same or different material properties. For example, thefirst material can be more compressible than the second material. Foranother example, the first material can include closed cells and thesecond material can include open cells.

In some embodiments of the aspects disclosed herein, the heat controlmember can include a plurality of layers. For example, the heat controlmember can include at least one layer of or including a thermallyconductive material, e.g., a layer including metal, carbon, thermallyconductive polymer, or combinations thereof. As used in the context ofthese embodiments, thermally conductive material refers to materialshaving a thermal conductivity greater than that of the aerogelcomposition. In certain embodiments, thermally conductive materials havethermal conductivities at least about one order of magnitude greaterthan that of the aerogel composition. In some embodiments, the heatcontrol member can include a plurality of layers of the aerogelcomposition. In certain embodiments, the heat control member can includeat least one layer of conductive material disposed adjacent to theaerogel composition. In certain embodiments, the heat control member caninclude at least one layer of conductive material disposed between atleast two of a plurality of layers of the aerogel composition. In someembodiments, the heat control member can include particles of theconductive material disposed within a layer of the heat control member,e.g., within a layer of the aerogel composition.

In exemplary embodiments, the heat control member can include amaterials or layers of material providing thermal capacitance (i.e., athermally capacitive material), e.g., a material having a specific heatcapacity of at least about 0.3 J/(g-C). In some embodiments, thematerial providing thermal capacitance has a specific heat capacity ofat least about 0.5 J/(g-C). For example, the material providing thermalcapacity can include metals such as aluminum, titanium, nickel, steel,iron, or combinations thereof. In some embodiments, the heat controlmember can include a layer or coating of the material providing thermalcapacitance. In some embodiments, the heat control member can includeparticles of the material providing thermal capacitance disposed withina layer of the heat control member, e.g., within a layer of the aerogelcomposition. In certain embodiments, the heat control member can includeat least one layer of a material providing thermal capacitance disposedadjacent to the aerogel composition. In certain embodiments, the heatcontrol member can include at least one layer of a material providingthermal capacitance disposed between at least two of a plurality oflayers of the aerogel composition. In exemplary embodiments, the heatcontrol member can include both thermally conductive and thermallycapacitive materials. For example, the heat control member can include amaterial that provides both thermal capacitance and thermalconductivity, e.g., a metal such as aluminum, titanium, nickel, steel,iron, or combinations thereof. For another example, the heat controlmember can include one or more different materials or layers of materialthat each provide either thermal capacitance, thermal conductivity, or acombination thereof, e.g., a layer including metal and a layer includingthermally conductive polymer.

In some embodiments, thermal pastes can be used between layers of theheat control member to ensure even and consistent thermal conductionbetween such layers. As used herein, thermal paste refers to variousmaterials also known as thermal compound, thermal grease, thermalinterface material (TIM), thermal gel, heat paste, heat sink compound,and heat sink paste. For example, a layer of thermal paste can bedisposed between the aerogel composition and other layers such as thelayer or layers including thermally conductive or thermally capacitivematerials.

In embodiments of the aspects disclosed herein, the composition canfurther include at least one facing layer, as discussed in more detailbelow. For example, the facing layer can be a layer selected from thegroup consisting of a polymeric sheet, a metallic sheet, a fibroussheet, and a fabric sheet. In exemplary embodiments, the facing layercan include the conductive material, the material providing thermalcapacity, or a combination thereof. In some embodiments, the facinglayer can be attached to the composition, e.g., by an adhesive mechanismselected from the consisting of: an aerosol adhesive, a urethane-basedadhesive, an acrylate adhesive, a hot melt adhesive, an epoxy, a rubberresin adhesive; a polyurethane composite adhesive, and combinationsthereof. In some embodiments, the facing layer can be attached to thecomposition by a non-adhesive mechanism, e.g., a mechanism selected fromthe group consisting of flame bonding, stitching, sealing bags, rivets,buttons, clamps, wraps, braces, and combinations thereof. In someembodiments, a combination of any of the aforementioned adhesive andnon-adhesive mechanisms can be used to attach a facing layer to thecomposition. In some embodiments of the above aspects, the heat controlmember can further include at least one layer of conductive material orthermally capacitive material. For example, the at least one layer ofconductive or thermally capacitive material can include metal, carbon,conductive polymer, or combinations thereof. In some examples, the atleast one layer of conductive material comprising carbon can be a highlyoriented graphite material, e.g., a pyrolytic graphite sheet or similarmaterial.

In embodiments of the aspects disclosed herein, the one or moreadditives are selected from the group consisting of boron carbide,diatomite, manganese ferrite, MnO, NiO, SnO, Ag₂O, Bi₂O₃, carbon black,graphite, titanium oxide, iron titanium oxide, aluminum oxide, zirconiumsilicate, zirconium oxide, iron (II) oxide, iron (III) oxide, manganesedioxide, iron titanium oxide (ilmenite), chromium oxide, siliconcarbide, titanium carbide, tungsten carbide, or mixtures thereof. Incertain embodiments, the one or more additives can include siliconcarbide. In particular embodiments, the one or more additives excludeswhiskers or fibers of silicon carbide.

In some embodiments, the aerogel composition further includes one ormore additional additives. For example, the one or more additionaladditives include fire-class additives. In these or other embodiments ofthe above aspects, the composition is low-flammable, non-flammable,low-combustible, or non-combustible. In some embodiments, the additivesinclude a clay mineral, for example, kaolin. In these or otherembodiments, the one or more additives include a combination offire-class additives and opacifers.

Furthermore, aerogel materials or framework of the various embodimentsof the present disclosure are practiced with aerogel particle-basedslurries or suspensions infiltrated into the reinforcement materialsdescribed in various embodiments. Various embodiments of the presentdisclosure may be practiced with non-particulate aerogel materialsproduced in-situ by infiltrating the reinforcement materials withvarious gel precursors in suitable solvent and followed by the removalof the solvent using various methods, including using supercriticalfluids, or at elevated temperatures and ambient pressures or atsub-critical pressures.

In separate embodiments, the current disclosure includes a heat controlmember including an aerogel composition, e.g., OCMF-reinforced orfiber-reinforced aerogel composition, comprising one or more—or evenall—of the foregoing features and characteristics, including variouscombinations and methods of manufacture thereof.

Embodiments of the thermal barriers and aerogel compositions disclosedherein are useful for separating, insulating and protecting batterycells or battery components of batteries of any configuration, e.g.,pouch cells, cylindrical cells, prismatic cells, as well as packs andmodules incorporating or including any such cells. The thermal barriersand aerogel compositions disclosed herein are useful in lithium ionbatteries, solid state batteries, and any other energy storage device ortechnology in which separation, insulation, and protection arenecessary.

These and other important objects, advantages, and features of theinvention will become clear as this disclosure proceeds.

The invention accordingly comprises the features of construction,combination of elements, and arrangement of parts that will beexemplified in the disclosure set forth hereinafter and the scope of theinvention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a chart showing heat control members controllingtime-to-temperature behavior according to certain embodiments disclosedherein;

FIG. 2 is a chart showing heat control members controllingtime-to-temperature behavior according to certain embodiments disclosedherein;

FIG. 3 is a chart showing a relationship between stress and strain forheat control members according to certain embodiments disclosed herein;

FIG. 4 is a chart showing a heat control member controllingtime-to-temperature behavior according to certain embodiments disclosedherein;

FIG. 5 is an exemplary heat control member according to certainembodiments disclosed herein,

FIG. 6 schematically illustrates a heat control member according tocertain embodiments disclosed herein;

FIG. 7 schematically illustrates a heat control member according tocertain embodiments disclosed herein;

FIG. 7 schematically illustrates a heat control member according tocertain embodiments disclosed herein;

FIG. 8 schematically illustrates a heat control member according tocertain embodiments disclosed herein.

FIG. 9 schematically illustrates a heat control member according tocertain embodiments disclosed herein.

DETAILED DESCRIPTION

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings, which form a partthereof, and within which are shown by way of illustration specificembodiments by which the invention may be practiced. It is to beunderstood that other embodiments may be utilized and structural changesmay be made without departing from the scope of the invention.

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” include plural referents unless the contentclearly dictates otherwise. As used in this specification and theappended claims, the term “or” is generally employed in its senseincluding “and/or” unless the context clearly dictates otherwise.

As used herein, “about” means approximately or nearly and in the contextof a numerical value or range set forth means ±5% of the numerical. Inan embodiment, the term “about” can include traditional roundingaccording to significant figures of the numerical value. In addition,the phrase “about ‘x′ to ‘y′” includes “about ‘x′ to about ‘y’”.

As used herein, the terms “composition” and “composite” are usedinterchangeably.

Aerogels are a class of porous materials with open-cells comprising aframework of interconnected structures, with a corresponding network ofpores integrated within the framework, and an interstitial phase withinthe network of pores primarily comprised of gases such as air. Aerogelsare typically characterized by a low density, a high porosity, a largesurface area, and small pore sizes. Aerogels can be distinguished fromother porous materials by their physical and structural properties.

Within the context of the present disclosure, the term “aerogel” or“aerogel material” refers to a gel comprising a framework ofinterconnected structures, with a corresponding network ofinterconnected pores integrated within the framework, and containinggases such as air as a dispersed interstitial medium; and which ischaracterized by the following physical and structural properties(according to Nitrogen Porosimetry Testing) attributable to aerogels:(a) an average pore diameter ranging from about 2 nm to about 100 nm,(b) a porosity of at least 80% or more, and (c) a surface area of about100 m²/g or more.

Aerogel materials of the present disclosure thus include any aerogels orother open-celled materials which satisfy the defining elements setforth in previous paragraphs; including materials which can be otherwisecategorized as xerogels, cryogels, ambigels, microporous materials, andthe like.

Aerogel materials may also be further characterized by additionalphysical properties, including: (d) a pore volume of about 2.0 mL/g ormore, particularly about 3.0 mL/g or more, (e) a density of about 0.50g/cc or less, particularly about 0.3 g/cc or less, more particularlyabout 0.25 g/cc or less; and (f) at least 50% of the total pore volumecomprising pores having a pore diameter of between 2 and 50 nm (althoughembodiments disclosed herein include aerogel frameworks and compositionsthat include pores having a pore diameter greater than 50 nm, asdiscussed in more detail below). However, satisfaction of theseadditional properties is not required for the characterization of acompound as an aerogel material.

Within the context of the present disclosure, the term “innovativeprocessing and extraction techniques” refers to methods of replacing aliquid interstitial phase in a wet-gel material with a gas such as air,in a manner which causes low pore collapse and low shrinkage to theframework structure of the gel. Drying techniques, such as ambientpressure evaporation, often introduce strong capillary pressures andother mass transfer limitations at the liquidvapor interface of theinterstitial phase being evaporated or removed. The strong capillaryforces generated by liquid evaporation or removal can cause significantpore shrinkage and framework collapse within the gel material. The useof innovative processing and extraction techniques during the extractionof a liquid interstitial phase reduces the negative effects of capillaryforces on the pores and the framework of a gel during liquid extraction(also referred to as solvent removal or drying).

In certain embodiments, an innovative processing and extractiontechnique uses near critical or supercritical fluids, or near criticalor super critical conditions, to extract the liquid interstitial phasefrom a wet-gel material. This can be accomplished by removing the liquidinterstitial phase from the gel near or above the critical point of theliquid or mixture of liquids. Co-solvents and solvent exchanges can beused to optimize the near critical or super critical fluid extractionprocess.

In certain embodiments, an innovative processing and extractiontechnique includes the modification of the gel framework to reduce theirreversible effects of capillary pressures and other mass transferlimitations at the liquid-vapor interface. This embodiment can includethe treatment of a gel framework with a hydrophobizing agent, or otherfunctionalizing agents, which allow a gel framework to withstand orrecover from any collapsing forces during liquid extraction conductedbelow the critical point of the liquid interstitial phase. Thisembodiment can also include the incorporation of functional groups orframework elements, which provide a framework modulus that issufficiently high to withstand or recover from collapsing forces duringliquid extraction conducted below the critical point of the liquidinterstitial phase.

Within the context of the present disclosure, the terms “framework” or“framework structure” refer to a network of interconnected oligomers,polymers, or particles that form the solid structure of a material.Within the context of the present disclosure, the terms “aerogelframework” or “aerogel framework structure” refer to the network ofinterconnected oligomers, polymers, or colloidal particles that form thesolid structure of a gel or an aerogel. The polymers or particles thatmake up the aerogel framework structure typically have a diameter ofabout 100 angstroms. However, framework structures of the presentdisclosure may also include networks of interconnected oligomers,polymers, or colloidal particles of all diameter sizes that form thesolid structure within a material such as a gel or aerogel. Furthermore,the terms “silica-based aerogel” or “silica-based aerogel framework”refer to an aerogel framework in which silica comprises at least 50% (byweight) of the oligomers, polymers, or colloidal particles that form thesolid framework structure within in the gel or aerogel.

Within the context of the present disclosure, the term “aerogelcomposition” refers to any composite material that includes aerogelmaterial as a component of the composite. Examples of aerogelcompositions include, but are not limited to fiber-reinforced aerogelcomposites; aerogel composites which include additive elements such asopacifiers, aerogel composites reinforced by open-cell macroporousframeworks; aerogel-polymer composites; and composite materials whichincorporate aerogel particulates, particles, granules, beads, or powdersinto a solid or semi-solid material, such as in conjunction withbinders, resins, cements, foams, polymers, or similar solid materials.Aerogel compositions are generally obtained after the removal of thesolvent from various gel materials disclosed herein. Aerogelcompositions thus obtained may further be subjected to additionalprocessing or treatment.

The various gel materials may also be subjected to additional processingor treatment otherwise known or useful in the art before subjected tosolvent removal (or liquid extraction or drying).

Within the context of the present disclosure, the term “monolithic”refers to aerogel materials in which a majority (by weight) of theaerogel included in the aerogel material or composition is in the formof a unitary interconnected aerogel nanostructure. Monolithic aerogelmaterials include aerogel materials which are initially formed to have aunitary interconnected gel or aerogel nanostructure, but which aresubsequently cracked, fractured, or segmented into non-unitary aerogelnanostructures. Monolithic aerogel materials are differentiated fromparticulate aerogel materials. The term “particulate aerogel material”refers to aerogel materials in which a majority (by weight) of theaerogel included in the aerogel material is in the form of particulates,particles, granules, beads, or powders, which can be combined orcompressed together but which lack an interconnected aerogelnanostructure between individual particles.

Within the context of the present disclosure, the term “wet gel” refersto a gel in which the mobile interstitial phase within the network ofinterconnected pores is primarily comprised of a liquid, such as aconventional solvent, liquefied gases like liquid carbon dioxide, or acombination thereof. Aerogels typically require the initial productionof a wet gel, followed by innovative processing and extraction toreplace the mobile interstitial liquid in the gel with air. Examples ofwet gels include, but are not limited to alcogels, hydrogels, ketogels,carbonogels, and any other wet gels known to those in the art.

Aerogel compositions of the present disclosure may comprise reinforcedaerogel compositions. Within the context of the present disclosure, theterm “reinforced aerogel composition” refers to aerogel compositionscomprising a reinforcing phase within the aerogel material, where thereinforcing phase is not part of the aerogel framework itself. Thereinforcing phase may be any material that provides increasedflexibility, resilience, conformability, or structural stability to theaerogel material. Examples of well-known reinforcing materials include,but are not limited to open-cell macroporous framework reinforcementmaterials, closed-cell macroporous framework reinforcement materials,open-cell membranes, honeycomb reinforcement materials, polymericreinforcement materials, and fiber reinforcement materials such asdiscrete fibers, woven materials, non-woven materials, needlednon-wovens, battings, webs, mats, and felts.

Within the context of the present disclosure, the term “fiber-reinforcedaerogel composition” refers to a reinforced aerogel composition whichcomprises a fiber reinforcement material as a reinforcing phase.Examples of fiber reinforcement materials include, but are not limitedto, discrete fibers, woven materials, non-woven materials, batts,battings, webs, mats, felts, or combinations thereof. Fiberreinforcement materials can comprise a range of materials, including,but not limited to: Polyesters, polyolefin terephthalates,poly(ethylene) naphthalate, polycarbonates (examples Rayon, Nylon),cotton, (e.g. lycra manufactured by DuPont), carbon (e.g. graphite),polyacrylonitriles (PAN), oxidized PAN, uncarbonized heat treated PANs(such as those manufactured by SGL carbon), glass or fiberglass basedmaterial (like S-glass, 901 glass, 902 glass, 475 glass, E-glass) silicabased fibers like quartz, (e.g. Quartzel manufactured by Saint-Gobain),Q-felt (manufactured by Johns Manville), Saffil (manufactured bySaffil), Durablanket (manufactured by Unifrax) and other silica fibers,Duraback (manufactured by Carborundum). Polyaramid fibers like Kevlar,Nomex, Sontem (all manufactured by DuPont), Conex (manufactured byTaijin), polyolefins like Tyvek (manufactured by DuPont), Dyneema(manufactured by DSM), Spectra (manufactured by Honeywell), otherpolypropylene fibers like Typar, Xavan (both manufactured by DuPont),fluoropolymers like PTFE with trade names as Teflon (manufactured byDuPont), Goretex (manufactured by W.L. GORE), Silicon carbide fiberslike Nicalon (manufactured by COI Ceramics), ceramic fibers like Nextel(manufactured by 3M), Acrylic polymers, fibers of wool, silk, hemp,leather, suede, PBO-Zylon fibers (manufactured by Tyobo), Liquid crystalmaterial like Vectan (manufactured by Hoechst), Cambrelle fiber(manufactured by DuPont), Polyurethanes, polyamaides, Wood fibers,Boron, Aluminum, Iron, Stainless Steel fibers and other thermoplasticslike PEEK, PES, PEI, PEK, PPS. The glass or fiberglass-based fiberreinforcement materials may be manufactured using one or moretechniques. In certain embodiments, it is desirable to make them using acarding and cross-lapping or air-laid process. In exemplary embodiments,carded and cross-lapped glass or fiberglass-based fiber reinforcementmaterials provide certain advantages over air-laid materials. Forexample, carded and cross-lapped glass or fiberglass-based fiberreinforcement materials can provide a consistent material thickness fora given basis weight of reinforcement material. In certain additionalembodiments, it is desirable to further needle the fiber reinforcementmaterials with a need to interlace the fibers in z-direction forenhanced mechanical and other properties in the final aerogelcomposition.

Reinforced aerogel compositions of the present disclosure may compriseaerogel compositions reinforced with open-cell macroporous frameworkmaterials. Within the context of the present disclosure, the term“open-cell macroporous framework” or “OCMF” refers to a porous materialcomprising a framework of interconnected structures of substantiallyuniform composition, with a corresponding network of interconnectedpores integrated within the framework, and which is characterized by anaverage pore diameter ranging from about 10 µm to about 700 µm Suchaverage pore diameter may be measured by known techniques, including butnot limited to, Microscopy with optical analysis. OCMF materials of thepresent disclosure thus include any open-celled materials that satisfythe defining elements set forth in this paragraph, including compoundsthat can be otherwise categorized as foams, foam-like materials,macroporous materials, and the like. OCMF materials can bedifferentiated from materials comprising a framework of interconnectedstructures that have a void volume within the framework and that do nothave a uniform composition, such as collections of fibers and bindershaving a void volume within the fiber matrix.

Within the context of the present disclosure, the term “substantiallyuniform composition” refers to uniformity in the composition of thereferred material within 10% tolerance.

Within the context of the present disclosure, the term “OCMF-reinforcedaerogel composition” refers to a reinforced aerogel compositioncomprising an open-cell macroporous framework material as a reinforcingphase. Suitable OCMF materials for use in the present disclosureinclude, but are not limited to, OCMF materials made from organicpolymeric materials. Examples include OCMF materials made frompolyolefins, polyurethanes, phenolics, melamine, cellulose acetate, andpolystyrene. Within the context of the present disclosure, the term“organic OCMF” refers to OCMF materials having a framework comprisedprimarily of organic polymeric materials. OCMF materials made frommelamine or melamine derivatives are also preferred in certainembodiments. Within the context of the present disclosure, the terms“melamine OCMF” or “melamine-based OCMF” refer to organic OCMF materialshaving a framework comprised primarily of polymeric materials derivedfrom reacting melamine with a condensation agent, such as formaldehyde.Examples of OCMF materials made from melamine or melamine derivativesfor use in the present disclosure are presented in U.S. Pat. Nos8,546,457; 4,666,948, and WO 2001/094436.The term “inorganic OCMF”refers to OCMF materials having a framework comprised primarily ofinorganic materials. Examples of inorganic OCMF include, but not limitedto, cementous materials, gypsum, and calcium silicate.

Within the context of the present disclosure, the term “foam” refers toa material comprising a framework of interconnected polymeric structuresof substantially uniform composition, with a corresponding network orcollection of pores integrated within the framework, and which is formedby dispersing a proportion of gas in the form of bubbles into a liquidor resin foam material such that the gas bubbles are retained as poresas the foam material solidifies into a solid structure. In general,foams can be made using a wide variety of processes — see, for example,U.S. Pat. Nos. 6,147,134; 5,889,071; 6,187,831; and 5,229,429. Foammaterials of the present disclosure thus include any materials thatsatisfy the defining elements set forth in this paragraph, includingcompounds that can be otherwise categorized as OCMF materials,macroporous materials, and the like. Foams as defined in the presentdisclosure may be in the types of thermoplastics, elastomers, andthermosets (duromers).

The pores within a solid framework can also be referred to as “cells”.Cells can be divided by cell walls or membranes, creating a collectionof independent closed pores within the porous material. The term “closedcell” refers to porous materials in which at least 50% of the porevolume is [substantially] confined cells enclosed by membranes or walls.Cells in a material can also be interconnected through cell openings,creating a network of interconnected open pores within the material. Theterm “open cell” refers to porous materials in which at least 50% of thepore volume is open cells. The open-cell material may comprise areticulated open-cell material, a non-reticulated open-cell material, ora combination thereof. Reticulated materials are open cell materialsproduced through a reticulation process that eliminates or puncturescell membranes within the porous material. Reticulated materialstypically have a higher concentration of open cells than non-reticulatedmaterials, but tend to be more expensive and difficult to produce.Generally, no porous material has entirely one type of cell structure(open cell or closed cell). Porous materials may be made using a widevariety of processes, including foam production processes presented inU.S. Pat. Nos. 6,147,134; 5,889,071; 6,187,831; 5,229,429; 4,454,248;and US Patent Application No 2007/0213417.

Within the context of the present disclosure, the terms “aerogelblanket” or “aerogel blanket composition” refer to aerogel compositionsreinforced with a continuous sheet of reinforcement material. Aerogelblanket compositions can be differentiated from other reinforced aerogelcompositions that are reinforced with a non-continuous reinforcementmaterial, such as separated agglomerates or clumps of reinforcementmaterials. Aerogel blanket compositions are particularly useful forapplications requiring flexibility, since they are highly conformableand may be used like a blanket to cover surfaces of simple or complexgeometry, while also retaining the excellent thermal insulationproperties of aerogels.

Within the context of the present disclosure, the terms “flexible” and“flexibility” refer to the ability of an aerogel material or compositionto be bent or flexed without macrostructural failure. Aerogelcompositions of the present disclosure are capable of bending at least5°, at least 25°, at least 45°, at least 65°, or at least 85° withoutmacroscopic failure; and/or have a bending radius of less than 4 feet,less than 2 feet, less than 1 foot, less than 6 inches, less than 3inches, less than 2 inches, less than 1 inch, or less than ½ inchwithout macroscopic failure. Likewise, the terms “highly flexible” or“high flexibility” refer to aerogel materials or compositions capable ofbending to at least 90° and/or have a bending radius of less than ½ inchwithout macroscopic failure. Furthermore, the terms “classifiedflexible” and “classified as flexible” refer to aerogel materials orcompositions which can be classified as flexible according to ASTM C1101(ASTM International, West Conshohocken, PA).

Aerogel compositions of the present disclosure can be flexible, highlyflexible, and/or classified flexible. Aerogel compositions of thepresent disclosure can also be drapable. Within the context of thepresent disclosure, the terms “drapable” and “drapability” refer to theability of an aerogel material or composition to be bent or flexed to90° or more with a radius of curvature of about 4 inches or less,without macroscopic failure. Aerogel materials or compositions accordingto certain embodiments of the current disclosure are flexible such thatthe composition is non-rigid and may be applied and conformed tothree-dimensional surfaces or objects, or pre-formed into a variety ofshapes and configurations to simplify installation or application.

Within the context of the present disclosure, the terms “additive” or“additive element” refer to materials that may be added to an aerogelcomposition before, during, or after the production of the aerogel.Additives may be added to alter or improve desirable properties in anaerogel, or to counteract undesirable properties in an aerogel.Additives are typically added to an aerogel material either prior togelation to precursor liquid, during gelation to a transition statematerial or after gelation to a solid or semi solid material. Examplesof additives include, but are not limited to microfibers, fillers,reinforcing agents, stabilizers, thickeners, elastic compounds,opacifiers, coloring or pigmentation compounds, radiation absorbingcompounds, radiation reflecting compounds, fire-class additives,corrosion inhibitors, thermally conductive components, componentsproviding thermal capacitance, phase change materials, pH adjustors,redox adjustors, HCN mitigators, off-gas mitigators, electricallyconductive compounds, electrically dielectric compounds, magneticcompounds, radar blocking components, hardeners, anti-shrinking agents,and other aerogel additives known to those in the art. In someembodiments, components providing thermal capacity can include materialshaving a specific heat capacity of at least about 0.3 J/(g-C). In someembodiments, the material providing thermal capacitance has a specificheat capacity of at least about 0.5 J/(g-C). For example, the materialproviding thermal capacity can include metals such as aluminum,titanium, nickel, steel, iron, or combinations thereof. In someembodiments, the heat control member can include a layer or coating ofthe material providing thermal capacitance. In some embodiments, theheat control member can include particles of the material providingthermal capacitance disposed within a layer of the heat control member.In certain embodiments, the heat control member can include at least onelayer of a material providing thermal capacitance disposed adjacent tothe aerogel composition. In certain embodiments, the heat control membercan include at least one layer of a material providing thermalcapacitance disposed between at least two of a plurality of layers ofthe aerogel composition.

In certain embodiments, the aerogel compositions, reinforced aerogelcompositions, and heat control members disclosed herein can performduring high temperature events, e.g., provide thermal protection duringhigh temperature events as disclosed herein. High temperature events arecharacterized by a sustained heat flux of at least about 25 kW/m², atleast about 30 kW/m², at least about 35 kW/m² or at least about 40 kW/m²over an area of at least about 1 cm² for at least 2 seconds. A heat fluxof about 40 kW/m² has been associated with that arising from typicalfires (Behavior of Charring Solids under Fire-Level Heat Fluxes;Milosavljevic, I., Suuberg, E.M.; NISTIR 5499; September 1994). In aspecial case, the high temperature event is a heat flux of heat flux ofabout 40 kW/m over an area of at least about 10 cm² for a duration of atleast 1 minute. Within the context of the present disclosure, the terms“thermal conductivity” and “TC” refer to a measurement of the ability ofa material or composition to transfer heat between two surfaces oneither side of the material or composition, with a temperaturedifference between the two surfaces. Thermal conductivity isspecifically measured as the heat energy transferred per unit time andper unit surface area, divided by the temperature difference. It istypically recorded in SI units as mW/m*K (milliwatts per meter *Kelvin). The thermal conductivity of a material may be determined bytest methods known in the art, including, but not limited to Test Methodfor Steady-State Thermal Transmission Properties by Means of the HeatFlow Meter Apparatus (ASTM C518, ASTM International, West Conshohocken,PA); a Test Method for Steady-State Heat Flux Measurements and ThermalTransmission Properties by Means of the Guarded-Hot-Plate Apparatus(ASTM C177, ASTM International, West Conshohocken, PA); a Test Methodfor Steady-State Heat Transfer Properties of Pipe Insulation (ASTM C335,ASTM International, West Conshohocken, PA); a Thin Heater ThermalConductivity Test (ASTM C1114, ASTM International, West Conshohocken,PA); Standard Test Method for Thermal Transmission Properties ofThermally Conductive Electrical Insulation Materials (ASTM D5470, ASTMInternational, West Conshohocken, PA); Determination of thermalresistance by means of guarded hot plate and heat flow meter methods (EN12667, British Standards Institution, United Kingdom); or Determinationof steady-state thermal resistance and related properties -Guarded hotplate apparatus (ISO 8203, International Organization forStandardization, Switzerland). Due to different methods possiblyresulting in different results, it should be understood that within thecontext of the present disclosure and unless expressly stated otherwise,thermal conductivity measurements are acquired according to ASTM C518standard (Test Method for Steady-State Thermal Transmission Propertiesby Means of the Heat Flow Meter Apparatus), at a temperature of about37.5° C. at atmospheric pressure in ambient environment, and under acompression load of about 2 psi. The measurements reported as per ASTMC518 typically correlate well with any measurements made as per EN 12667with any relevant adjustment to the compression load. In certainembodiments, aerogel materials or compositions of the present disclosurehave a thermal conductivity of about 40 mW/mK or less, about 30 mW/mK orless, about 25 mW/mK or less, about 20 mW/mK or less, about 18 mW/mK orless, about 16 mW/mK or less, about 14 mW/mK or less, about 12 mW/mK orless, about 10 mW/mK or less, about 5 mW/mK or less, or in a rangebetween any two of these values.

Thermal conductivity measurements can also be acquired at a temperatureof about 10° C. at atmospheric pressure under compression. Thermalconductivity measurements at 10° C. are generally 0.5-0.7 mW/mK lowerthan corresponding thermal conductivity measurements at 37.5° C. Incertain embodiments, aerogel materials or compositions of the presentdisclosure have a thermal conductivity at 10° C. of about 40 mW/mK orless, about 30 mW/mK or less, about 25 mW/mK or less, about 20 mW/mK orless, about 18 mW/mK or less, about 16 mW/mK or less, about 14 mW/mK orless, about 12 mW/mK or less, about 10 mW/mK or less, about 5 mW/mK orless, or in a range between any two of these values.

Within the context of the present disclosure, the term “density” refersto a measurement of the mass per unit volume of an aerogel material orcomposition. The term “density” generally refers to the apparent densityof an aerogel material, as well as the bulk density of an aerogelcomposition. Density is typically recorded as kg/m³ or g/cc. The densityof an aerogel material or composition may be determined by methods knownin the art, including, but not limited to Standard Test Method forDimensions and Density of Preformed Block and Board-Type ThermalInsulation (ASTM C303, ASTM International, West Conshohocken, PA);Standard Test Methods for Thickness and Density of Blanket or BattThermal Insulations (ASTM C167, ASTM International, West Conshohocken,PA); Determination of the apparent density of preformed pipe insulation(EN 13470, British Standards Institution, United Kingdom); orDetermination of the apparent density of preformed pipe insulation (ISO18098, International Organization for Standardization, Switzerland). Dueto different methods possibly resulting in different results, it shouldbe understood that within the context of the present disclosure, densitymeasurements are acquired according to ASTM C167 standard (Standard TestMethods for Thickness and Density of Blanket or Batt ThermalInsulations) at 2 psi compression for thickness measurement, unlessotherwise stated. In certain embodiments, aerogel materials orcompositions of the present disclosure have a density of about 0.60 g/ccor less, about 0.50 g/cc or less, about 0.40 g/cc or less, about 0.30g/cc or less, about 0.25 g/cc or less, about 0.20 g/cc or less, about0.18 g/cc or less, about 0.16 g/cc or less, about 0.14 g/cc or less,about 0.12 g/cc or less, about 0.10 g/cc or less, about 0.05 g/cc orless, about 0.01 g/cc or less, or in a range between any two of thesevalues.

Within the context of the present disclosure, the term “hydrophobicity”refers to a measurement of the ability of an aerogel material orcomposition to repel water.

Hydrophobicity of an aerogel material or composition may be expressed interms of the liquid water uptake. Within the context of the presentdisclosure, the term “liquid water uptake” refers to a measurement ofthe potential of an aerogel material or composition to absorb orotherwise retain liquid water. Liquid water uptake can be expressed as apercent (by weight or by volume) of water that is absorbed or otherwiseretained by an aerogel material or composition when exposed to liquidwater under certain measurement conditions. The liquid water uptake ofan aerogel material or composition may be determined by methods known inthe art, including, but not limited to Standard Test Method forDetermining the Water Retention (Repellency) Characteristics of FibrousGlass Insulation (ASTM C1511, ASTM International, West Conshohocken,PA); Standard Test Method for Water Absorption by Immersion of ThermalInsulation Materials (ASTM C1763, ASTM International, West Conshohocken,PA); Thermal insulating products for building applications:Determination of short term water absorption by partial immersion (EN1609, British Standards Institution, United Kingdom). Due to differentmethods possibly resulting in different results, it should be understoodthat within the context of the present disclosure, measurements ofliquid water uptake are acquired according to ASTM C1511 standard(Standard Test Method for Determining the Water Retention (Repellency)Characteristics of Fibrous Glass Insulation), under ambient pressure andtemperature, unless otherwise stated. In certain embodiments, aerogelmaterials or compositions of the present disclosure can have a liquidwater uptake of about 50 wt% or less, about 40 wt% or less, about 30 wt%or less, about 20 wt% or less, about 15 wt% or less, about 10 wt% orless, about 8 wt% or less, about 3 wt% or less, about 2 wt% or less,about 1 wt% or less, about 0.1 wt% or less, or in a range between anytwo of these values. An aerogel material or composition that hasimproved liquid water uptake relative to another aerogel material orcomposition will have a lower percentage of liquid wateruptake/retention relative to the reference aerogel materials orcompositions.

Hydrophobicity of an aerogel material or composition can be expressed interms of the water vapor uptake. Within the context of the presentdisclosure, the term “water vapor uptake” refers to a measurement of thepotential of an aerogel material or composition to absorb water vapor.Water vapor uptake can be expressed as a percent (by weight) of waterthat is absorbed or otherwise retained by an aerogel material orcomposition when exposed to water vapor under certain measurementconditions. The water vapor uptake of an aerogel material or compositionmay be determined by methods known in the art, including, but notlimited to Standard Test Method for Determining the Water Vapor Sorptionof Unfaced Mineral Fiber Insulation (ASTM C1104, ASTM International,West Conshohocken, PA); Thermal insulating products for buildingapplications: Determination of long term water absorption by diffusion(EN 12088, British Standards Institution, United Kingdom). Due todifferent methods possibly resulting in different results, it should beunderstood that within the context of the present disclosure,measurements of water vapor uptake are acquired according to ASTM C1104standard (Standard Test Method for Determining the Water Vapor Sorptionof Unfaced Mineral Fiber Insulation) at 49° C. and 95% humidity for 24hours (modified from 96 hours according to the ASTM C 1104 standard)under ambient pressure, unless otherwise stated. In certain embodiments,aerogel materials or compositions of the present disclosure can have awater vapor uptake of about 50 wt% or less, about 40 wt% or less, about30 wt% or less, about 20 wt% or less, about 15 wt% or less, about 10 wt%or less, about 8 wt% or less, about 3 wt% or less, about 2 wt% or less,about 1 wt% or less, about 0.1 wt% or less, or in a range between anytwo of these values. An aerogel material or composition that hasimproved water vapor uptake relative to another aerogel material orcomposition will have a lower percentage of water vapor uptake/retentionrelative to the reference aerogel materials or compositions.

Hydrophobicity of an aerogel material or composition can be expressed bymeasuring the equilibrium contact angle of a water droplet at theinterface with the surface of the material. Aerogel materials orcompositions of the present disclosure can have a water contact angle ofabout 90° or more, about 120° or more, about 130° or more, about 140° ormore, about 150° or more, about 160° or more, about 170° or more, about175° or more, or in a range between any two of these values.

Within the context of the present disclosure, the terms “heat ofcombustion”, “HOC” and “ΔHc” refer to a measurement of the amount ofheat energy released in the combustion or exothermic thermaldecomposition of a material or composition. Heat of combustion istypically recorded in calories of heat energy released per gram ofaerogel material or composition (cal/g), or as megajoules of heat energyreleased per kilogram of material or composition (MJ/kg). The heat ofcombustion of a material or composition may be determined by methodsknown in the art, including, but not limited to Reaction to fire testsfor products - Determination of the gross heat of combustion (calorificvalue) (EN ISO 1716, International Organization for Standardization,Switzerland; EN adopted). Within the context of the present disclosure,heat of combustion measurements are acquired according to EN ISO 1716standards (Reaction to fire tests for products - Determination of thegross heat of combustion (calorific value)), unless otherwise stated. Incertain embodiments, aerogel compositions of the present disclosure mayhave a heat of combustion of about 750 cal/g or less, about 717 cal/g orless, about 700 cal/g or less, about 650 cal/g or less, about 600 cal/gor less, about 575 cal/g or less, about 550 cal/g or less, about 500cal/g or less, about 450 cal/g or less, about 400 cal/g or less, about350 cal/g or less, about 300 cal/g or less, about 250 cal/g or less,about 200 cal/g or less, about 150 cal/g or less, about 100 cal/g orless, about 50 cal/g or less, about 25 cal/g or less, about 10 cal/g orless, or in a range between any two of these values. An aerogelcomposition that has an improved heat of combustion relative to anotheraerogel composition will have a lower heat of combustion value, relativeto the reference aerogel compositions. In certain embodiments of thepresent disclosure, the HOC of an aerogel composite is improved byincorporating a fire-class additive into the aerogel composite.

Within the context of the present disclosure, all thermal analyses andrelated definitions are referenced with measurements performed bystarting at 25° C. and ramping at a rate of 20° C. per minute up to1000° C. in air at ambient pressure. Accordingly, any changes in theseparameters will have to be accounted for (or re-performed under theseconditions) in measuring and calculating onset of thermal decomposition,temperature of peak heat release, temperature of peak hear absorptionand the like. Within the context of the present disclosure, the terms“onset of thermal decomposition” and “T_(D)” refer to a measurement ofthe lowest temperature of environmental heat at which rapid exothermicreactions from the decomposition of organic material appear within amaterial or composition. The onset of thermal decomposition of organicmaterial within a material or composition may be measured usingthermo-gravimetric analysis (TGA). The TGA curve of a material depictsthe weight loss (%mass) of a material as it is exposed to an increase insurrounding temperature, thus indicating thermal decomposition. Theonset of thermal decomposition of a material can be correlated with theintersection point of the following tangent lines of the TGA curve: aline tangent to the base line of the TGA curve, and a line tangent tothe TGA curve at the point of maximum slope during the rapid exothermicdecomposition event related to the decomposition of organic material.Within the context of the present disclosure, measurements of the onsetof thermal decomposition of organic material are acquired using TGAanalysis as provided in this paragraph, unless otherwise stated.

The onset of thermal decomposition of a material may also be measuredusing differential scanning calorimetry (DSC) analysis. The DSC curve ofa material depicts the heat energy (mW/mg) released by a material as itis exposed to a gradual increase in surrounding temperature. The onsetof thermal decomposition temperature of a material can be correlatedwith the point in the DSC curve where the Δ mW/mg (change in the heatenergy output) maximally increases, thus indicating exothermic heatproduction from the aerogel material. Within the context of the presentdisclosure, measurements of onset of thermal decomposition using DSC,TGA, or both are acquired using a temperature ramp rate of 20° C./min asfurther defined in the previous paragraph, unless otherwise statedexpressly. DSC and TGA each provide similar values for this onset ofthermal decomposition, and many times, the tests are run concurrently,so that results are obtained from both. In certain embodiments, aerogelmaterials or compositions of the present disclosure have an onset ofthermal decomposition of about 300° C. or more, about 320° C. or more,about 340° C. or more, about 360° C. or more, about 380° C. or more,about 400° C. or more, about 420° C. or more, about 440° C. or more,about 460° C. or more, about 480° C. or more, about 500° C. or more,about 550° C. or more, about 600° C. or more, or in a range between anytwo of these values. Within the context herein, for example, a firstcomposition having an onset of thermal decomposition that is higher thanan onset of thermal decomposition of a second composition, would beconsidered an improvement of the first composition over the secondcomposition. It is contemplated herein that onset of thermaldecomposition of a composition or material is increased when adding oneor more fire-class additives, as compared to a composition that does notinclude any fire-class additives.

Within the context of the present disclosure, the terms “onset ofendothermic decomposition” and “T_(ED)” refer to a measurement of thelowest temperature of environmental heat at which endothermic reactionsfrom decomposition or dehydration appear within a material orcomposition. The onset of endothermic decomposition of a material orcomposition may be measured using thermo-gravimetric analysis (TGA). TheTGA curve of a material depicts the weight loss (%mass) of a material asit is exposed to an increase in surrounding temperature. The onset ofthermal decomposition of a material may be correlated with theintersection point of the following tangent lines of the TGA curve: aline tangent to the base line of the TGA curve, and a line tangent tothe TGA curve at the point of maximum slope during the rapid endothermicdecomposition or dehydration of the material. Within the context of thepresent disclosure, measurements of the onset of endothermicdecomposition of a material or composition are acquired using TGAanalysis as provided in this paragraph, unless otherwise stated.

Within the context of the present disclosure, the terms “furnacetemperature rise” and “ΔT_(R)” refer to a measurement of the differencebetween a maximum temperature (T_(MAX)) of a material or compositionunder thermal decomposition conditions relative to a baselinetemperature of that material or composition under the thermaldecomposition conditions (usually the final temperature, or T_(FIN)).Furnace temperature rise is typically recorded in degrees Celsius, or°C. The furnace temperature rise of a material or composition may bedetermined by methods known in the art, including, but not limited toReaction to fire tests for building and transport products:Non-combustibility test (EN ISO 1182, International Organization forStandardization, Switzerland; EN adopted). Within the context of thepresent disclosure, furnace temperature rise measurements are acquiredaccording to conditions comparable to EN ISO 1182 standard (Reaction tofire tests for building and transport products: Non-combustibilitytest), unless otherwise stated. In certain embodiments, aerogelcompositions of the present disclosure can have a furnace temperaturerise of about 100° C. or less, about 90° C. or less, about 80° C. orless, about 70° C. or less, about 60° C. or less, about 50° C. or less,about 45° C. or less, about 40° C. or less, about 38° C. or less, about36° C. or less, about 34° C. or less, about 32° C. or less, about 30° C.or less, about 28° C. or less, about 26° C. or less, about 24° C. orless, or in a range between any two of these values. Within the contextof compositional stability at elevated temperatures, for example, afirst composition having a furnace temperature rise that is lower than afurnace temperature rise of a second composition, would be considered animprovement of the first composition over the second composition. It iscontemplated herein that furnace temperature rise of a composition isreduced when adding one or more fire-class additives, as compared to acomposition that does not include any fire-class additives.

Within the context of the present disclosure, the terms “flame time” and“T_(FLAME)” refer to a measurement of sustained flaming of a material orcomposition under thermal decomposition conditions, where “sustainedflaming” is a persistence of flame at any part on the visible part ofthe specimen lasting 5 seconds or longer. Flame time is typicallyrecorded in seconds or minutes. The flame time of a material orcomposition may be determined by methods known in the art, including,but not limited to Reaction to fire tests for building and transportproducts: Non-combustibility test (EN ISO 1182, InternationalOrganization for Standardization, Switzerland; EN adopted). Within thecontext of the present disclosure, flame time measurements are acquiredaccording to conditions comparable to EN ISO 1182 standard (Reaction tofire tests for building and transport products: Non-combustibilitytest), unless otherwise stated. In certain embodiments, aerogelcompositions of the present disclosure have a flame time of about 30seconds or less, about 25 seconds or less, about 20 seconds or less,about 15 seconds or less, about 10 seconds or less, about 5 seconds orless, about 2 seconds or less, or in a range between any two of thesevalues. Within the context herein, for example, a first compositionhaving a flame time that is lower than a flame time of a secondcomposition, would be considered an improvement of the first compositionover the second composition. It is contemplated herein that flame timeof a composition is reduced when adding one or more fire-classadditives, as compared to a composition that does not include anyfire-class additives.

Within the context of the present disclosure, the terms “mass loss” and“ΔM” refer to a measurement of the amount of a material, composition, orcomposite that is lost or burned off under thermal decompositionconditions. Mass loss is typically recorded as weight percent or wt%.The mass loss of a material, composition, or composite may be determinedby methods known in the art, including, but not limited to: Reaction tofire tests for building and transport products: Non-combustibility test(EN ISO 1182, International Organization for Standardization,Switzerland; EN adopted). Within the context of the present disclosure,mass loss measurements are acquired according to conditions comparableto EN ISO 1182 standard (Reaction to fire tests for building andtransport products: Non-combustibility test), unless otherwise stated.In certain embodiments, aerogel compositions of the present disclosurecan have a mass loss of about 50% or less, about 40% or less, about 30%or less, about 28% or less, about 26% or less, about 24% or less, about22% or less, about 20% or less, about 18% or less, about 16% or less, orin a range between any two of these values. Within the context herein,for example, a first composition having a mass loss that is lower than amass loss of a second composition would be considered an improvement ofthe first composition over the second composition. It is contemplatedherein that mass loss of a composition is reduced when adding one ormore fire-class additives, as compared to a composition that does notinclude any fire-class additives.

Within the context of the present disclosure, the terms “temperature ofpeak heat release” refers to a measurement of the temperature ofenvironmental heat at which exothermic heat release from decompositionis at the maximum. The temperature of peak heat release of a material orcomposition may be measured using TGA analysis, differential scanningcalorimetry (DSC) or a combination thereof. DSC and TGA each wouldprovide similar values for temperature of peak heat release, and manytimes, the tests are run concurrently, so that results are obtained fromboth. In a typical DSC analysis, heat flow is plotted against the risingtemperature and temperature of peak heat release is the temperature atwhich the highest peak in such curve occurs. Within the context of thepresent disclosure, measurements of the temperature of peak heat releaseof a material or composition are acquired using TGA analysis as providedin this paragraph, unless otherwise stated.

In the context of an endothermic material, the terms “temperature ofpeak heat absorption” refers to a measurement of the temperature ofenvironmental heat at which endothermic heat absorption fromdecomposition is at the minimum. The temperature of peak heat absorptionof a material or composition may be measured using TGA analysis,differential scanning calorimetry (DSC) or a combination thereof. In atypical DSC analysis, heat flow is plotted against the risingtemperature and temperature of peak heat absorption is the temperatureat which the lowest peak in such curve occurs. Within the context of thepresent disclosure, measurements of the temperature of peak heatabsorption of a material or composition are acquired using TGA analysisas provided in this paragraph, unless otherwise stated.

Within the context of the present disclosure, the term“low-flammability” and “low-flammable” refer to a material orcomposition which satisfy the following combination of properties: i) afurnace temperature rise of 50° C. or less; ii) a flame time of 20seconds or less; and iii) a mass loss of 50 wt% or less. Within thecontext of the present disclosure, the term “non-flammability” and“non-flammable” refer to a material or composition which satisfy thefollowing combination of properties: i) a furnace temperature rise of40° C. or less; ii) a flame time of 2 seconds or less, and iii) a massloss of 30 wt% or less. It is contemplated that flammability (e.g.,combination of furnace temperature rise, flame time, and mass loss) of acomposition is reduced upon inclusion of one or more fire-classadditives, as described herein.

Within the context of the present disclosure, the term“low-combustibility” and “low-combustible” refer to a low-flammablematerial or composition which has a total heat of combustion (HOC) lessthan or equal to 3 MJ/kg. Within the context of the present disclosure,the term “non-combustibility” and “non-combustible” refer to anon-flammable material or composition which has the heat of combustion(HOC) less than or equal to 2 MJ/kg. It is contemplated that HOC of acomposition is reduced upon inclusion of one or more fire-classadditives, as described herein.

Aerogels are described as a framework of interconnected structures thatare most commonly comprised of interconnected oligomers, polymers, orcolloidal particles. An aerogel framework may be made from a range ofprecursor materials, including inorganic precursor materials (such asprecursors used in producing silica-based aerogels); organic precursormaterials (such precursors used in producing carbon-based aerogels);hybrid inorganic/organic precursor materials; and combinations thereof.Within the context of the present disclosure, the term “amalgam aerogel”refers to an aerogel produced from a combination of two or moredifferent gel precursors; the corresponding precursors are referred toas “amalgam precursors”.

Inorganic aerogels are generally formed from metal oxide or metalalkoxide materials. The metal oxide or metal alkoxide materials may bebased on oxides or alkoxides of any metal that can form oxides. Suchmetals include, but are not limited to silicon, aluminum, titanium,zirconium, hafnium, yttrium, vanadium, cerium, and the like. Inorganicsilica aerogels are traditionally made via the hydrolysis andcondensation of silica-based alkoxides (such as tetraethoxylsilane), orvia gelation of silicic acid or water glass. Other relevant inorganicprecursor materials for silica based aerogel synthesis include, but arenot limited to metal silicates such as sodium silicate or potassiumsilicate, alkoxysilanes, partially hydrolyzed alkoxysilanes,tetraethoxylsilane (TEOS), partially hydrolyzed TEOS, condensed polymersof TEOS, tetramethoxylsilane (TMOS), partially hydrolyzed TMOS,condensed polymers of TMOS, tetra-n-propoxysilane, partially hydrolyzedand/or condensed polymers of tetra-n-propoxysilane, polyethylsilicates,partially hydrolyzed polyethysilicates, monomeric alkylalkoxy silanes,bis-trialkoxy alkyl or aryl silanes, polyhedral silsesquioxanes, orcombinations thereof.

In certain embodiments of the present disclosure, pre-hydrolyzed TEOS,such as Silbond H-5 (SBH5, Silbond Corp), which is hydrolyzed with awater/silica ratio of about 1.9-2, may be used as commercially availableor may be further hydrolyzed prior to incorporation into the gellingprocess. Partially hydrolyzed TEOS or TMOS, such as polyethysilicate(Silbond 40) or polymethylsilicate may also be used as commerciallyavailable or may be further hydrolyzed prior to incorporation into thegelling process.

Inorganic aerogels can also include gel precursors comprising at leastone hydrophobic group, such as alkyl metal alkoxides, cycloalkyl metalalkoxides, and aryl metal alkoxides, which can impart or improve certainproperties in the gel such as stability and hydrophobicity. Inorganicsilica aerogels can specifically include hydrophobic precursors such asalkylsilanes or arylsilanes. Hydrophobic gel precursors may be used asprimary precursor materials to form the framework of a gel material.However, hydrophobic gel precursors are more commonly used asco-precursors in combination with simple metal alkoxides in theformation of amalgam aerogels. Hydrophobic inorganic precursor materialsfor silica based aerogel synthesis include, but are not limited totrimethyl methoxysilane (TMS), dimethyl dimethoxysilane (DMS), methyltrimethoxysilane (MTMS), trimethyl ethoxysilane, dimethyl diethoxysilane(DMDS), methyl triethoxysilane (MTES), ethyl triethoxysilane (ETES),diethyl diethoxysilane, dimethyl diethoxysilane (DMDES), ethyltriethoxysilane, propyl trimethoxysilane, propyl triethoxysilane, phenyltrimethoxysilane, phenyl triethoxysilane (PhTES), hexamethyldisilazaneand hexaethyldisilazane, and the like. Any derivatives of any of theabove precursors may be used and specifically certain polymeric of otherchemical groups may be added or cross-linked to one or more of the aboveprecursors.

Aerogels may also be treated to impart or improve hydrophobicity.Hydrophobic treatment can be applied to a sol-gel solution, a wet-gelprior to liquid extraction, or to an aerogel subsequent to liquidextraction. Hydrophobic treatment is especially common in the productionof metal oxide aerogels, such as silica aerogels. An example of ahydrophobic treatment of a gel is discussed below in greater detail,specifically in the context of treating a silica wet-gel. However, thespecific examples and illustrations provided herein are not intended tolimit the scope of the present disclosure to any specific type ofhydrophobic treatment procedure or aerogel substrate. The presentdisclosure can include any gel or aerogel known to those in the art, aswell as associated methods of hydrophobic treatment of the aerogels, ineither wet-gel form or dried aerogel form.

Hydrophobic treatment is carried out by reacting a hydroxy moiety on agel, such as a silanol group (Si—OH) present on a framework of a silicagel, with a functional group of a hydrophobizing agent. The resultingreaction converts the silanol group and the hydrophobizing agent into ahydrophobic group on the framework of the silica gel. The hydrophobizingagent compound can react with hydroxyl groups on the gel according thefollowing reaction: R_(N)MX_(4-N) (hydrophobizing agent) + MOH (silanol)→ MOMR_(N) (hydrophobic group) + HX. Hydrophobic treatment can takeplace both on the outer macro-surface of a silica gel, as well as on theinner-pore surfaces within the porous network of a gel.

A gel can be immersed in a mixture of a hydrophobizing agent and anoptional hydrophobic-treatment solvent in which the hydrophobizing agentis soluble, and which is also miscible with the gel solvent in thewet-gel. A wide range of hydrophobic-treatment solvents can be used,including solvents such as methanol, ethanol, isopropanol, xylene,toluene, benzene, dimethylformamide, and hexane. Hydrophobizing agentsin liquid or gaseous form may also be directly contacted with the gel toimpart hydrophobicity.

The hydrophobic treatment process can include mixing or agitation tohelp the hydrophobizing agent to permeate the wet-gel. The hydrophobictreatment process can also include varying other conditions such astemperature and pH to further enhance and optimize the treatmentreactions. After the reaction is completed, the wet-gel is washed toremove unreacted compounds and reaction by-products.

Hydrophobizing agents for hydrophobic treatment of an aerogel aregenerally compounds of the formula: R_(N)MX₄-_(N); where M is the metal;R is a hydrophobic group such as CH₃, CH₂CH₃, C₆H₆, or similarhydrophobic alkyl, cycloalkyl, or aryl moieties; and X is a halogen,usually C1. Specific examples of hydrophobizing agents include, but arenot limited to trimethylchlorosilane (TMCS), triethylchlorosilane(TECS), triphenylchlorosilane (TPCS), dimethylchlorosilane (DMCS),dimethyldichlorosilane (DMDCS), and the like. Hydrophobizing agents canalso be of the formula: Y(R₃M)₂; where M is a metal; Y is bridging groupsuch as NH or O; and R is a hydrophobic group such as CH₃, CH₂CH₃, C₆H₆,or similar hydrophobic alkyl, cycloalkyl, or aryl moieites. Specificexamples of such hydrophobizing agents include, but are not limited tohexamethyldisilazane [HMDZ] and hexamethyldisiloxane [HMDSO].Hydrophobizing agents can further include compounds of the formula:R_(N)MV₄._(N),wherein V is a reactive or leaving group other than ahalogen. Specific examples of such hydrophobizing agents include, butare not limited to vinyltriethoxysilane and vinyltrimethoxysilane.

Hydrophobic treatments of the present disclosure may also be performedduring the removal, exchange or drying of liquid in the gel. In aspecific embodiment, the hydrophobic treatment may be performed insupercritical fluid environment (such as, but not limited tosupercritical carbon dioxide) and may be combined with the drying orextraction step.

Within the context of the present disclosure, the term“hydrophobic-bound silicon” refers to a silicon atom within theframework of a gel or aerogel comprising at least one hydrophobic groupcovalently bonded to the silicon atom. Examples of hydrophobic-boundsilicon include, but are not limited to, silicon atoms in silica groupswithin the gel framework which are formed from gel precursors comprisingat least one hydrophobic group (such as MTES or DMDS). Hydrophobic-boundsilicon may also include, but are not limited to, silicon atoms in thegel framework or on the surface of the gel which are treated with ahydrophobizing agent (such as HMDZ) to impart or improve hydrophobicityby incorporating additional hydrophobic groups into the composition.Hydrophobic groups of the present disclosure include, but are notlimited to, methyl groups, ethyl groups, propyl groups, isopropylgroups, butyl groups, isobutyl groups, tertbutyl groups, octyl groups,phenyl groups, or other substituted or unsubstituted hydrophobic organicgroups known to those with skill in the art. Within the context of thepresent disclosure, the terms “hydrophobic group,” “hydrophobic organicmaterial,” and “hydrophobic organic content” specifically excludereadily hydrolysable organic silicon-bound alkoxy groups on theframework of the gel material, which are the product of reactionsbetween organic solvents and silanol groups. Such excluded groups aredistinguishable from hydrophobic organic content of this through NMRanalysis. The amount of hydrophobic-bound silicon contained in anaerogel can be analyzed using NMR spectroscopy, such as CP/MAS ²⁹SiSolid State NMR. An NMR analysis of an aerogel allows for thecharacterization and relative quantification of M-type hydrophobic-boundsilicon (monofunctional silica, such as TMS derivatives); D-typehydrophobic-bound silicon (bifunctional silica, such as DMDSderivatives); T-type hydrophobic-bound silicon (trifunctional silica,such as MTES derivatives); and Q-type silicon (quadfunctional silica,such as TEOS derivatives). NMR analysis can also be used to analyze thebonding chemistry of hydrophobic-bound silicon contained in an aerogelby allowing for categorization of specific types of hydrophobic-boundsilicon into sub-types (such as the categorization of T-typehydrophobic-bound silicon into T¹ species, T² species, and T³ species).Specific details related to the NMR analysis of silica materials can befound in the article “Applications of Solid-State NMR to the Study ofOrganic/Inorganic Multicomponent Materials” by Geppi et al.,specifically pages 7-9 (Appl. Spec. Rev. (2008), 44-1: 1-89), which ishereby incorporated by reference according to the specifically citedpages.

The characterization of hydrophobic-bound silicon in a CP/MAS ²⁹Si NMRanalysis can be based on the following chemical shift peaks: M¹ (30 to10 ppm); D¹ (10 to -10 ppm), D² (-10 to -20 ppm); T¹ (-30 to -40 ppm).T² (-40 to -50 ppm), T³ (-50 to -70 ppm); Q² (-70 to -85 ppm), Q³ (-85to -95 ppm), Q⁴ (-95 to -110 ppm). These chemical shift peaks areapproximate and exemplary, and are not intended to be limiting ordefinitive. The precise chemical shift peaks attributable to the varioussilicon species within a material can depend on the specific chemicalcomponents of the material, and can generally be deciphered throughroutine experimentation and analysis by those in the art.

Within the context of the present disclosure, the term “hydrophobicorganic content” or “hydrophobe content” or “hydrophobic content” refersto the amount of hydrophobic organic material bound to the framework inan aerogel material or composition. The hydrophobic organic content ofan aerogel material or composition can be expressed as a weightpercentage of the amount of hydrophobic organic material on the aerogelframework relative to the total amount of material in the aerogelmaterial or composition. Hydrophobic organic content can be calculatedby those with ordinary skill in the art based on the nature and relativeconcentrations of materials used in producing the aerogel material orcomposition. Hydrophobic organic content can also be measured usingthermo-gravimetric analysis (TGA) of the subject materials, preferablyin oxygen atmosphere (though TGA under alternate gas environments arealso useful). Specifically, the percentage of hydrophobic organicmaterial in an aerogel can be correlated with the percentage of weightloss in a hydrophobic aerogel material or composition when subjected tocombustive heat temperatures during a TGA analysis, with adjustmentsbeing made for the loss of moisture, loss of residual solvent, and theloss of readily hydrolysable alkoxy groups during the TGA analysis.Other alternative techniques such as differential scanning calorimetry,elemental analysis (particularly, carbon), chromatographic techniques,nuclear magnetic resonance spectra and other analytical techniques knownto person of skilled in the art may be used to measure and determinehydrophobe content in the aerogel compositions of the presentdisclosure. In certain instances, a combination of the known techniquesmay be useful or necessary in determining the hydrophobe content of theaerogel compositions of the present disclosure.

Aerogel materials or compositions of the present disclosure can have ahydrophobic organic content of 50 wt% or less, 40 wt% or less, 30 wt% orless, 25 wt% or less, 20 wt% or less, 15 wt% or less, 10 wt% or less, 8wt% or less, 6 wt% or less, 5 wt% or less, 4 wt% or less, 3 wt% or less,2 wt% or less, 1 wt% or less, or in a range between any two of thesevalues.

The term “fuel content” refers to the total amount of combustiblematerial in an aerogel material or composition, which can be correlatedwith the total percentage of weight loss in an aerogel material orcomposition when subjected to combustive heat temperatures during a TGAor TG-DSC analysis, with adjustments being made for the loss ofmoisture. The fuel content of an aerogel material or composition caninclude hydrophobic organic content, as well as other combustibleresidual alcoholic solvents, filler materials, reinforcing materials,and readily hydrolysable alkoxy groups.

Organic aerogels are generally formed from carbon-based polymericprecursors. Such polymeric materials include, but are not limited toresorcinol formaldehydes (RF), polyimide, polyacrylate, polymethylmethacrylate, acrylate oligomers, polyoxyalkylene, polyurethane,polyphenol, polybutadiane, trialkoxysilyl-terminatedpolydimethylsiloxane, polystyrene, polyacrylonitrile, polyfurfural,melamine-formaldehyde, cresol formaldehyde, phenol-furfural, polyether,polyol, polyisocyanate, polyhydroxybenze, polyvinyl alcohol dialdehyde,polycyanurates, polyacrylamides, various epoxies, agar, agarose,chitosan, and combinations thereof. As one example, organic RF aerogelsare typically made from the sol-gel polymerization of resorcinol ormelamine with formaldehyde under alkaline conditions.

Organic/inorganic hybrid aerogels are mainly comprised of (organicallymodified silica (“ormosil”) aerogels. These ormosil materials includeorganic components that are covalently bonded to a silica network.Ormosils are typically formed through the hydrolysis and condensation oforganically modified silanes, R—Si(OX)₃, with traditional alkoxideprecursors. Y(OX)4. In these formulas, X may represent, for example,CH₃, C₂H₅, C₃H₇, C₄H₉. Y may represent, for example, Si, Ti, Zr, or Al;and R may be any organic fragment such as methyl, ethyl, propyl, butyl,isopropyl, methacrylate, acrylate, vinyl, epoxide, and the like. Theorganic components in ormosil aerogel may also be dispersed throughoutor chemically bonded to the silica network.

Within the context of the present disclosure, the term “ormosil”encompasses the foregoing materials as well as other organicallymodified materials, sometimes referred to as “ormocers.” Ormosils areoften used as coatings where an ormosil film is cast over a substratematerial through, for example, the sol-gel process. Examples of otherorganic-inorganic hybrid aerogels of the disclosure include, but are notlimited to, silica-polyether, silica-PMMA, silica-chitosan, carbides,nitrides, and other combinations of the aforementioned organic andinorganic aerogel forming compounds. Published US Pat. App. 20050192367(Paragraphs [0022]-[0038] and [0044]-[0058]) includes teachings of suchhybrid organic-inorganic materials, and is hereby incorporated byreference according to the individually cited sections and paragraphs.

In certain embodiments, aerogels of the present disclosure are inorganicsilica aerogels formed primarily from prepolymerized silica precursorspreferably as oligomers, or hydrolyzed silicate esters formed fromsilicon alkoxides in an alcohol solvent. In certain embodiments, suchprepolymerized silica precursors or hydrolyzed silicate esters may beformed in situ from other precurosrs or silicate esters such as alkoxysilanes or water glass. However, the disclosure as a whole may bepracticed with any other aerogel compositions known to those in the art,and is not limited to any one precursor material or amalgam mixture ofprecursor materials.

As discussed above, aerogel compositions according to embodiments of thepresent disclosure provide favorable properties for compressibility,compressional resilience, and compliance. When used as a separatorbetween cells within a battery module, thermal insulation sheets formedusing aerogel compositions can provide resistance to compressiondeformation to accommodate the expansion of cells due to the degradationand swelling of active materials during charge/discharge cycles for thebattery. During initial assembly of a battery module, a relatively lowload of 1 MPa or lower is typically applied to the cell separatormaterials, e.g., the reinforced aerogel compositions disclosed herein.When the cells within a battery module expand or swell duringcharge/discharge cycles, a load of up to about 5 MPa may be applied tothe cell separator materials, e.g., the reinforced aerogel compositionsdisclosed herein. Accordingly, compressibility, compressional resilienceand compliance of the cell separator materials are important properties.

In an exemplary aspect, the present disclosure provides a heat controlmember including a aerogel composition where the heat control memberexhibits a compressibility of less than about 25% at about 25 kPa.Optionally, upon release of compression, the heat control member can besufficiently resilient to return to at least about 80%, 75% 65%, 60% or50%, of its original thickness. In some embodiments, the heat controlmember exhibits a compressibility of less than about 25% in a range ofabout 25 kPa to about 35 kPa and preferably a compressibility less thanabout 50% at about 50 kPa. In some embodiments, the heat control memberexhibits a compressibility in the range of about 25% to about 50P/o atabout 50 kPa. In exemplary embodiments, the heat control member exhibitsa compressibility of less than about 80% at about 245 kPa, e.g., lessthan about 70% at about 235 kPa. In exemplary embodiments, the heatcontrol member exhibits a compressibility of less than about 70% atabout 345 kPa. The thermal conductivity of the heat control memberincluding a reinforced aerogel composition is preferably maintained atless than about 25 mW/m*K when the heat control member is compressed.

As discussed above, aerogel compositions according to embodiments of thepresent disclosure can include an aerogel framework that includesmacropores. Without being bound by any particular theory of operation,the presence of macropores within the aerogel framework can allow forcompression of the aerogel composition, e.g., the reinforced aerogelcomposition, while maintaining, or even improving, the thermalproperties, e.g., reducing the thermal conductivity. For example, themacropores may be deformed, crushed, or otherwise reduced in size bycompression of the composition, thereby allowing for the thickness ofthe composition to be reduced under load. However, as the macropores aredeformed, they effectively become smaller pores. As a result, the pathfor heat transfer within the aerogel framework can be more tortuous asthe macropores are deformed, thereby improving thermal properties, e.g.,reducing the thermal conductivity. Within the context of the presentdisclosure, “mesopores” are pores for which the average pore diameter isin the range of about 2 nm and about 50 nm. Aerogel frameworks aretypically mesoporous (i.e., primarily containing pores with an averagediameter ranging from about 2 nm to about 50 nm). In certainembodiments, the aerogel framework of aerogel compositions of thepresent disclosure can include macropores. Within the context of thepresent disclosure, “macropores” are pores for which the average porediameter is greater than about 50 nm. An aerogel framework can includeboth macropores and mesopores. For example, at least 10% of a porevolume of the aerogel framework can be made up of macropores, at least5% of the pore volume of the aerogel framework can be made up ofmacropores, at least 75% of the pore volume of the aerogel framework canbe made up of macropores, at least 95% of the pore volume of the aerogelframework can be made up of macropores, or 100% of the pore volume ofthe aerogel framework can be made up of macropores. In some particularembodiments, the aerogel framework can be a macroporous aerogelframework such that a majority of its pore volume is made up ofmacropores. In some instances, the macroporous aerogel framework canalso include micropores and/or mesopores. In some embodiments, theaverage pore size (diameter) of pores in the aerogel framework can begreater than 50 nm, greater than 50 nm to 5000 nm, 250 nm to 2000 nm,500 nm to 2000 nm, 500 nm to 1400 nm, or 1200 nm. In certainembodiments, the average pore size can be greater than 50 nm indiameter, greater than 50 nm to 1000 nm, preferably 100 nm to 800 nm,more preferably 250 nm to 750 nm.

In some embodiments, the variation in pore size within the aerogelframework can be distributed homogenously through the aerogel framework.For example, the average pore size can be substantially the samethroughout the aerogel framework.

In other embodiments, the variation in pores size within the aerogelframework can be distributed heterogeneously through the aerogelframework. For example, the average pore size can be different incertain regions of the aerogel framework. In some exemplary embodiments,the average pore size can be greater in the region of the upper surface,the lower surface or both the upper and lower surfaces of the aerogelframework. For example, macropores can be distributed within thecomposition such that the ratio of macropores to mesopores is greater atthe upper surface than at the lower surface, greater at the lowersurface than at the upper surface, or greater at both the upper andlower surfaces than in a middle region between the upper and lowersurfaces. For another example, macropores can be distributed within thecomposition such that the ratio of macropores to mesopores is greaternear the upper surface than near the lower surface, greater near thelower surface than near the upper surface, or greater near both theupper and lower surfaces than in the middle region between the upper andlower surfaces. In other embodiments, the average pore size can begreater in a middle region between the upper and lower surface of theaerogel framework.

Macropores can be formed during production of the aerogel composition.For example, the formation of macropores can be induced in the gelprecursor materials during transition into the gel composition. In someembodiments, the formation of macropores can be through inducingspinodal decomposition, e.g., of the gel precursor solution. For anotherexample, the formation of macropores can be induced by the addition ofone or more foaming agents.

The macropores present in the resulting aerogel framework can be formedby selecting processing conditions that favor the formation ofmacropores vs mesopores and/or micropores. The amount of macropores canbe adjusted by implementing any one of, any combination of, or all ofthe following variables: (1) the polymerization solvent; (2) thepolymerization temperature; (3) the polymer molecular weight; (4) themolecular weight distribution; (5) the copolymer composition; (6) theamount of branching; (7) the amount of crosslinking; (8) the method ofbranching; (9) the method of crosslinking; (10) the method used information of the gel; (11) the type of catalyst used to form the gel;(12) the chemical composition of the catalyst used to form the gel; (13)the amount of the catalyst used to form the gel; (14) the temperature ofgel formation; (15) the type of gas flowing over the material during gelformation; (16) the rate of gas flowing over the material during gelformation; (17) the pressure of the atmosphere during gel formation;(18) the removal of dissolved gasses during gel formation; (19) thepresence of solid additives in the resin during gel formation; (20) theamount of time of the gel formation process; (21) the substrate used forgel formation; (22) the type of solvent or solvents used in each step ofthe solvent exchange process; (23) the composition of solvent orsolvents used in each step of the solvent exchange process; (24) theamount of time used in each step of the solvent exchange process; (25)the dwell time of the part in each step of the solvent exchange process;(26) the rate of flow of the solvent exchange solvent; (27) the type offlow of the solvent exchange solvent; (28) the agitation rate of thesolvent exchange solvent; (29) the temperature used in each step of thesolvent exchange process; (30) the ratio of the volume of solventexchange solvent to the volume of the part; (31) the method of drying;(32) the temperature of each step in the drying process; (33) thepressure in each step of the drying process; (34) the composition of thegas used in each step of the drying process; (35) the rate of gas flowduring each step of the drying process; (36) the temperature of the gasduring each step of the drying process; (37) the temperature of the partduring each step of the drying process; (38) the presence of anenclosure around the part during each step of the drying process; (39)the type of enclosure surrounding the part during drying; and/or (40)the solvents used in each step of the drying process. Themultifunctional amine and diamine compounds may be added separately ortogether in one or more portions as solids, neat, or dissolved in anappropriate solvent. In other aspects, a method of making an aerogel caninclude the steps of: (a) providing a multifunctional amine compound andat least one diamine compound to a solvent to form a solution; (b)providing at least one dianhydride compound to the solution of step (a)under conditions sufficient to form a branched polymer matrix solution,where the branched polymer matrix is solubilized in the solution; and(c) subjecting the branched polymer matrix solution to conditionssufficient to form an aerogel having an open-cell structure. Themacropores present in the resulting aerogel framework can be formed inthe manner noted above. In one preferred and non-limiting aspect, theformation of macropores vs smaller mesopores and micropores can beprimarily controlled by controlling the polymer/solvent dynamics duringgel formation.

As discussed above, aerogel compositions according to embodiments of thepresent disclosure can include an aerogel framework and a reinforcementmaterial where at least a portion of the reinforcement material does notcontain aerogel. For example, the aerogel framework can extend partiallythrough the thickness of the reinforcement material. In suchembodiments, a portion of the reinforcement material, e.g., an OCMF,fiber, or combinations thereof, can include aerogel material and aportion can be free of aerogel. For example, in some embodiments, theaerogel extends through about 90% of the thickness of the reinforcementmaterial, through a range of about 50% and about 90% of the thickness ofthe reinforcement material, through a range of about 10% to about 50% ofthe thickness of the reinforcement material, or through about 10% of thethickness of the reinforcement material.

Without being bound by any particular theory of operation, aerogelcompositions in which at least a portion of the reinforcement materialdoes not contain aerogel can provide favorable properties forcompressibility, compressional resilience, and compliance. For example,the properties of the reinforcement material can be selected to providesufficient reinforcement and support for thermal properties in theregion containing aerogel and also to provide sufficientcompressibility, compressional resilience, and/or compliance in theregion without aerogel. The aerogel-containing portion of the reinforcedaerogel composition can provide the desired thermal conductivity, e.g.,less than about 25 mW/m*K while the portion of the reinforcement withoutaerogel can provide or improve the desired physical characteristics,e.g., compressibility.

In some embodiments, reinforced aerogel compositions in which at least aportion of the reinforcement material does not contain aerogel can beformed using methods disclosed herein in which the reinforcementmaterial is combined with an amount of precursor solution sufficient topartially fill the reinforcement material with precursor solution. Forexample, the volume of precursor can be less than the volume of thereinforcement material such that the precursor extends only partiallythrough the reinforcement. When dried, the resulting reinforced aerogelcomposition will include an aerogel framework extending through lessthan the full thickness of the reinforcement material, as discussedabove. In other embodiments, reinforced aerogel compositions in which atleast a portion of the reinforcement material does not contain aerogelcan be formed by removing surface aerogel layers from the reinforcedaerogel composition.

In some embodiments, reinforced aerogel compositions in which at least aportion of the reinforcement material does not contain aerogel can beformed using a reinforcement material having mixed properties throughthe thickness of the reinforcement. For example, the reinforcement caninclude a plurality of layers, each layer having varying properties,e.g., differences in average pore/cell size, material composition,closed cells, open cells, surface treatments, or combinations thereof.The plurality of layers can be bonded to each other, e.g., using anadhesive, by flame bonding or by other suitable methods or mechanismssuch as those discussed herein. The different properties of thereinforcement material can provide a varied distribution of aerogelthrough the layers. For example, the open cell portion of thereinforcement material can include an aerogel framework while the closedcell portion remains substantially free of aerogel. Similarly, othermaterial properties of the reinforcement material or layers thereof candetermine the distribution of aerogel within the reinforcement and thuswithin the reinforced aerogel composition.

In some exemplary embodiments, reinforced aerogel compositions in whichat least a portion of the reinforcement material does not containaerogel can be formed using methods disclosed herein in which theproperties of the reinforcement material or layers or reinforcementmaterial control or affect the amount of precursor solution that fillsthat material or layer, e.g., during the casting process, so as toprovide partial filling of the reinforcement material with precursorsolution. For example, one layer of the reinforcement can have opencells and another layer of the reinforcement can have closed cells. Whena precursor solution is combined with such a reinforcement, the gelprecursor solution can infiltrate the open cells of that layer while notsubstantially infiltrating the closed cells of the other layer. Whensuch a composition is dried, the resulting reinforced aerogelcomposition can include a portion, e.g., the closed cell layer, thatdoes not contain aerogel while another portion, e.g., the open celllayer, contains aerogel.

In some embodiments, the additives disclosed herein (e.g., endothermicadditives, opacifying additives, fire-class additives, or otheradditives) can be heterogeneously dispersed within the reinforcedaerogel composition. For example, the additive material can vary throughthe thickness or along the length and/or width of the aerogelcomposition. For example, the additive can be accumulated on one side ofthe aerogel composition. In some embodiments, the additive material(s)can be concentrated in one layer of the aerogel composite or be providedas a separate layer consisting essentially of the additive adjacent toor attached to the composite. For example, the heat control member caninclude a layer consisting essentially of an endothermic material, suchas gypsum, sodium bicarbonate, magnesia-based cement. In furtherexemplary embodiments, the aerogel composition can also include at leastone layer of additional material, either within the composition or as afacing layer. For example, the layer can be a layer selected from thegroup consisting of a polymeric sheet, a metallic sheet, a fibroussheet, a highly oriented graphite material, e.g., a pyrolytic graphitesheet, and a fabric sheet. In some embodiments, the facing layer can beattached to the composition, e.g., by an adhesive mechanism selectedfrom the consisting of: an aerosol adhesive, a urethane-based adhesive,an acrylate adhesive, a hot melt adhesive, an epoxy, a rubber resinadhesive; a polyurethane composite adhesive, and combinations thereof.In some embodiments, the facing layer can be attached to the compositionby a non-adhesive mechanism, e.g., a mechanism selected from the groupconsisting of: flame bonding, needling, stitching, sealing bags, rivets,buttons, clamps, wraps, braces, and combinations thereof. In someembodiments, a combination of any of the aforementioned adhesive andnon-adhesive mechanisms can be used to attach a facing layer to thecomposition.

As discussed herein, aerogel compositions or composites can includematerials which incorporate aerogel particulates, particles, granules,beads, or powders into a solid or semisolid material, such as inconjunction with binders such as adhesives, resins, cements, foams,polymers, or similar solid or solidifying materials. For example,aerogel compositions can include a reinforcing material, aerogelparticles, and, optionally, a binder. In exemplary embodiments, a slurrycontaining aerogel particles and at least one type of wetting agent canbe provided. For example, the aerogel particles can be coated or wettedwith at least one wetting agent, such as a surfactant or dispersant. Theaerogel particles can be fully wetted, partially wetted (e.g., surfacewetting), or be present in a slurry. The preferred wetting agent iscapable of volatilizing to allow suitable recovery of the hydrophobicityof hydrophobic aerogel particles. If the wetting agent remains on thesurface of the aerogel particles, the remaining wetting agent cancontribute to the overall thermal conductivity of the compositematerial. Thus, the preferred wetting agent is one that is removeable,such as by volatilization with or without decomposition or other means.Generally, any wetting agent that is compatible with the aerogel can beused.

The slurry or aerogel coated with a wetting agent can be useful as a wayto easily introduce hydrophobic aerogel into a variety of materials,such as other aqueous-containing fluids, slurries, adhesives, bindermaterials, which can optionally harden to form solid materials, fibers,metalized fibers, discrete fibers, woven materials, non-woven materials,needled non-wovens, battings, webs, mats, felts, and combinationsthereof. The aerogel wetted with at least one wetting agent or theslurry containing the aerogel with at least one wetting agent permitsthe easy introduction and uniform distribution of hydrophobic aerogel.Wet laid processes, such as the ones described in U.S. Pat. Nos.9,399,864; 8,021,583; 7,635,411; and 5,399,422 (each of which areincorporated by reference herein in their entirety), use an aqueousslurry to disperse aerogel particles, fibers and other additives. Theslurry can then be dewatered to form a layer of aerogel particles,fibers and additives that can be dried and optionally calendared toproduce an aerogel composite.

In other embodiments, aerogel compositions can include aerogelparticles, at least one inorganic matrix material and, optionally,fibers, auxiliary materials, additives, and further inorganic binders.The inorganic matrix material can, in some embodiments, includephyllosilicates, e.g., naturally occurring phyllosilicates, such askaolins, clays or bentonites, synthetic phyllosilicates, such asmagadiite or kenyaite, or mixtures of these. The phyllosilicates may befired or unfired, e.g., to dry the materials and drive off the water ofcrystallization. The inorganic matrix material can also, in someembodiments, include inorganic binders, such as cement, lime, gypsum orsuitable mixtures thereof, in combination with phyllosilicates. Theinorganic matrix material can also, in some embodiments, include otherinorganic additives, such as fire-class additives, opacifiers, orcombinations thereof, disclosed herein. Exemplary processes and aerogelcompositions including inorganic matrix materials are disclosed in U.S.Pat. Nos. 6,143,400; 6,083,619 (each of which are incorporated byreference herein in their entirety).In some embodiments, aerogelcompositions can include aerogel particles coated on or absorbed withinwoven materials, non-woven materials, needled non-wovens, battings,webs, mats, felts, and combinations thereof. Adhesive binders can beincluded in the composition. Additives such as fire-class additives,opacifiers, or combinations thereof, as disclosed herein, can also beincluded. Exemplary processes and aerogel compositions coated on orabsorbed into fabrics are disclosed in U.S. Pat. Pub. No. 2019/0264381A1(which is incorporated by reference herein in its entirety)

As discussed herein, aerogel composites can be laminated or faced withother materials, such as reinforcing layers of facing materials. In oneembodiment, the present disclosure provides a multi-layer laminatecomprising at least one base layer including a reinforced aerogelcomposition, and at least one facing layer. In one embodiment, thefacing layer comprises a reinforcing material. In one embodiment, thereinforced aerogel composition is reinforced with a fiber reinforcementlayer or an open-cell foam reinforcement layer. In one embodiment, thepresent disclosure provides a multi-layer laminate comprising a baselayer comprising a reinforced aerogel composition, and at least twofacing layers comprising reinforcing materials, wherein the two facinglayers are on opposite surfaces of the base layer. For example, themulti-layer aerogel laminate composite can be produced according to themethods and materials described in U.S. Pat. Application 2007/0173157.

The facing layer can comprise materials which will help provide specificcharacteristics to the final composite structure, such as improvedflexibility or reduced dusting. The facing materials can be stiff orflexible. The facing materials can include conductive layers orreflective foils. For example, the facing materials can include metallicor metallized materials. The facing materials can include non-wovenmaterials. The facing layers can be disposed on a surface of thecomposite structure or the reinforced aerogel composites that form thecomposite structure, e.g., the heat control member. The facing layerscan form a continuous coating or bag around the composite structure orthe reinforced aerogel composites that form the composite structure,e.g., the heat control member. In some embodiments, the facing layer orlayers can encapsulate the composite structure or the reinforced aerogelcomposites that form the composite structure.

In one embodiment, the facing layer comprises a polymeric sheetsurrounding the composite structure; more specifically a polymericmaterial which comprises polyesters, polyethylenes, polyurethanes,polypropylenes, polyacrylonitriles, polyamids, aramids; and morespecifically polymers such as polyethyleneterphthalate, low densitypolyethylene, ethylene-propylene copolymers, poly(4-methyl-pentane),polytetrafluoroethylene, poly(1-butene), polystyrene, polyvinylacetatae,polyvinylchloride, polyvinylidenechloride, polyvinylfluoride,polyvinylacrylonitrile, plymethylmethacrylate, polyoxymethylene,polyphenylenesulfone, cellulosetriacetate, polycarbonate, polyethylenenaphthalate, polycaprolactam, polyhexamethyleneadipamide,polyundecanoamide, polyimide, or combinations thereof. In oneembodiment, the polymeric sheet comprises or consists essentially of anexpanded polymeric material; more specifically an expanded polymericmaterial comprising PTFE (ePTFE), expanded polypropylene (ePP), expandedpolyethylene (ePE), expanded polystyrene (ePS), or combinations thereof.In one preferred embodiment, the facing material consists essentially ofan expanded polymeric material. In one embodiment, the polymeric sheetcomprises or consists essentially of a microporous polymeric materialcharacterized by a pore size ranging from 0.1 µm to 210 µm, 0.1 µm to115 µm, 0.1 µm to 15 µm, or 0.1 µm to 0.6 µm.

In one embodiment, the facing layer material comprises or consistsessentially of a fluoropolymeric material. Within the context of thepresent disclosure, the terms “fluoropolymeric” or “fluoropolymermaterial” refer to materials comprised primarily of polymericfluorocarbons. Suitable fluoropolymeric facing layer materials include,but are not limited to: polytetrafluoroethylene (PTFE), includingmicroporous PTFE described in U.S. Pat. 5,814,405, and expanded PTFE(ePTFE) such as Gore-Tex® (available from W.L. Gore); polyvinylfluoride(PVF); polyvinylidene fluoride (PVDF); perfluoroalkoxy (PFA);fluorinated ethylene-propylene (FEP); Polychlorotrifluoroethylene(PCTFE); Ethylene tetrafluoroethylene (ETFE); polyvinylidene fluoride(PVDF); ethylene chlorotrifluoroethylene (ECTFE); and combinationsthereof. In one preferred embodiment, the facing material consistsessentially of a fluorpolymeric material. In one preferred embodiment,the facing material consists essentially of an expanded PTFE (ePTFE)material.

In one embodiment, the facing layer material comprises or consistsessentially of a non-fluorpolymeric material. Within the context of thepresent disclosure, the terms “non-fluoropolymeric” or“non-fluoropolymer material” refer to materials which do not comprise afluorpolymeric material. Suitable non-fluoropolymeric facing layermaterials include, but are not limited to: aluminized Mylar; low densitypolyethylene, such as Tyvek® (available from DuPont); rubber or rubbercomposites; non-woven materials, elastic fibers such as spandex, nylon,lycra or elastane; and combinations thereof. In one embodiment, thefacing material is a flexible facing material.

In some embodiments, the facing layer material can include automotiveresins and polymers such as those having a maximum use temperature up toabout 100 C, up to about 120 C or up to about 150 C. For example, thefacing layer material can include acrylonitrile butadiene styrene (ABS)polycarbonate ABS, polypropylene, polyurethane, polystyrene,polyethylene, polycarbonate, polymides, PVC, or combinations thereof.For example, aerogel composites and heat control members according toembodiments disclosed herein can include layers of automotive resins orautomotive polymers, metallic or metallized layers, and aerogel layers.

The facing layer can be attached to the base layer by using adhesiveswhich are suitable for securing inorganic or organic facing materials tothe reinforcing material of the base layer. Examples of adhesives whichcan be used in the present disclosure include, but are not limited to:cement-based adhesives, sodium silicates, latexes, pressure sensitiveadhesives, silicone, polystyrene, aerosol adhesives, urethane, acrylateadhesives, hot melt boding systems, boding systems commerciallyavailable from 3M, epoxy, rubber resin adhesives, polyurethane adhesivemixtures such as those described in U.S. Pat. 4,532,316.

The facing layer can also be attached to the base layer by usingnon-adhesive materials or techniques which are suitable for securinginorganic or organic facing materials to the reinforcing material of thebase layer. Examples of non-adhesive materials or techniques which canbe used in the present disclosure include, but are not limited to: heatsealing, ultrasonic stitching, RF sealing, stitches or threading,needling, sealing bags, rivets or buttons, clamps, wraps, or othernon-adhesive lamination materials.

The facing layer can be attached to the base layer at any stage ofproduction of the aerogel composite material. In one embodiment, thefacing layer is attached to the base layer after infusion of the sol gelsolution into the base reinforcement material but prior to gelation. Inanother embodiment, the facing layer is attached to the base layer afterinfusion of the sol gel solution into the base reinforcement materialand after subsequent gelation, but prior to aging or drying the gelmaterial. In yet another embodiment, the facing layer is attached to thebase layer after aging and drying the gel material. In a preferredembodiment, the facing layer is attached to the reinforcement materialof the base layer prior to infusion of the sol gel solution into thebase reinforcement material. The facing layer can be solid and fluidimpermeable. The facing layer can be porous and fluid permeable. In apreferred embodiment, the facing layer is porous and fluid permeable,and contains pores or holes with diameters large enough to allow fluidsto diffuse through the facing material. In another preferred embodiment,the facing layer is attached to the reinforcement material of the baselayer prior to infusion of the sol gel solution into the basereinforcement material, wherein the facing layer is porous and fluidpermeable, and contains pores or holes with diameters large enough toallow fluids to diffuse through the facing material. In yet anotherpreferred embodiment, the facing layer is attached to an open-cell foamreinforcement material prior to infusion of the sol gel solution intothe foam reinforcement material, wherein the facing layer is porous andfluid permeable, and contains pores or holes with diameters large enoughto allow fluids to diffuse through the facing material.

In some embodiments, the composite structure or the reinforced aerogelcomposites that form the composite structure may be encapsulated by anencapsulation member. For example, the encapsulation member can includea layer or layers of material surrounding the composite or compositestructure and/or a coating of material surrounding the composite orcomposite structure. For example, the encapsulation member can include afilm, a layer, an envelope or a coating. The encapsulation member can bemade of any material suitable to enclose the composite structure or thereinforced aerogel composites that form the composite structure. Forexample, the encapsulation member can reduce or eliminate the generationof dust or particulate material shed from the composite structure.

The encapsulation member may include at least one vent that allows airto flow in and out of the panel. The encapsulation member may include atleast one filter that filters particulate matter. In an exemplaryembodiment, the encapsulation member includes a vent that allows air toflow in and out of the panel, and a particulate filter over the ventthat keeps particulate matter within the encapsulation member. Inanother embodiment, the encapsulation member includes edge seals whichinclude at least one vent and at least one particulate filter. In afurther embodiment, the encapsulation member includes edge seals whichinclude at least one vent and at least one particulate filter, whereinthe vents in the edge seals allow air to flow in and out of theencapsulation member edges, and wherein the filters capture and retainparticulate matter in the flowing air to prevent contamination of theair outside the encapsulation member with particulate matter. In someembodiments of the above aspects, the heat control member can include aplurality of layers. For example, the heat control member can include atleast one layer of or including a thermally conductive material, e.g., alayer including metal, carbon, thermally conductive polymer, orcombinations thereof. As used in the context of these embodiments,thermally conductive material refers to materials having a thermalconductivity greater than that of the aerogel composition. In certainembodiments, thermally conductive materials have thermal conductivitiesat least about one order of magnitude greater than that of the aerogelcomposition. In some embodiments, the heat control member can include aplurality of layers of the aerogel composition. In certain embodiments,the heat control member can include at least one layer of conductivematerial disposed adjacent to the aerogel composition. In certainembodiments, the heat control member can include at least one layer ofconductive material disposed between at least two of a plurality oflayers of the aerogel composition. In some embodiments, the heat controlmember can include particles of the conductive material disposed withina layer of the heat control member, e.g., within a layer of the aerogelcomposition.

In exemplary embodiments, the heat control member can include amaterials or layers of material providing thermal capacitance (i.e., athermally capacitive material), e.g., a material having a specific heatcapacity of at least about 0.3 J/(g-C). In some embodiments, thematerial providing thermal capacitance has a specific heat capacity ofat least about 0.5 J/(g-C). For example, the material providing thermalcapacity can include metals such as aluminum, titanium, nickel, steel,iron, or combinations thereof. In some embodiments, the heat controlmember can include a layer or coating of the material providing thermalcapacitance. In some embodiments, the heat control member can includeparticles of the material providing thermal capacitance disposed withina layer of the heat control member, e.g., within a layer of the aerogelcomposition. In certain embodiments, the heat control member can includeat least one layer of a material providing thermal capacitance disposedadjacent to the aerogel composition. In certain embodiments, the heatcontrol member can include at least one layer of a material providingthermal capacitance disposed between at least two of a plurality oflayers of the aerogel composition. In exemplary embodiments, the heatcontrol member can include both thermally conductive and thermallycapacitive materials. For example, the heat control member can include amaterial that provides both thermal capacitance and thermalconductivity, e.g., a metal such as aluminum, titanium, nickel, steel,iron, or combinations thereof. For another example, the heat controlmember can include one or more different materials or layers of materialthat each provide either thermal capacitance, thermal conductivity, or acombination thereof, e.g., a layer including metal and a layer includingthermally conductive polymer.

In some embodiments, thermal pastes can be used between layers of theheat control member to ensure even and consistent thermal conductionbetween such layers. As used herein, thermal paste refers to variousmaterials also known as thermal compound, thermal grease, thermalinterface material (TIM), thermal gel, heat paste, heat sink compound,and heat sink paste. For example, a layer of thermal paste can bedisposed between the aerogel composition and any other layers such asthe layer or layers including thermally conductive or thermallycapacitive materials, the facing layer or layers, or the encapsulationmember.

As discussed herein, the heat control member can include multiple layersof material, such as insulating layers, thermally conductive layers,thermally capacitive layers, heat reflecting layers, compressible orcompliant layers, or combinations thereof. The combination of layers inthe heat control member can be selected to obtain the desiredcombination of properties, e.g., compressibility, resilience, thermalperformance, fire reaction, and other properties. In some embodiments,the heat control member includes at least one compliant member disposedbetween at least two layers of reinforced aerogel composition. Thecompliant member includes a compressible material, i.e., a material thatcan be compressed to reduce its thickness while providing a desiredresistance to compression. For example, the compliant member can be afoam or other compressible material such as polyolefins, polyurethanes,phenolics, melamine, cellulose acetate, or polystyrene. In certainembodiments, the heat control member can also include at least one layerof thermally conductive material or thermally capacitive materialdisposed between the at least one compliant member and at least one ofthe plurality of layers of the reinforced aerogel composition. Thethermally conductive material or thermally capacitive material canabsorb and/or disperse heat within the heat control member. In someembodiments, the heat control member can further include a heatreflecting layer. For example, the heat reflecting layer can include ametallic foil or sheet.

In embodiments of the heat control member that include several layers,the layers can be attached to other layers, e.g., by an adhesivemechanism selected from the consisting of: an aerosol adhesive, aurethane-based adhesive, an acrylate adhesive, a hot melt adhesive, anepoxy, a rubber resin adhesive; a polyurethane composite adhesive, andcombinations thereof. In some embodiments, the layers can be attached bya non-adhesive mechanism, e.g., a mechanism selected from the groupconsisting of: flame bonding, needling, stitching, sealing bags, rivets,buttons, clamps, wraps, braces, and combinations thereof. In someembodiments, a combination of any of the aforementioned adhesive andnon-adhesive mechanisms can be used to attach layers together.

FIG. 5 illustrates an exemplary heat control member according toembodiments disclosed herein. As illustrated in FIG. 6 , an exemplaryheat control member 10 includes a layer of reinforced aerogelcomposition 12. A layer of thermally conductive or thermally capacitivematerial 14 is disposed adjacent to the layer of reinforced aerogelcomposition 12. The heat control member 10 is substantially planar andhas a first major outer surface defined by an outer surface of the firstlayer of reinforced aerogel composition 12 and a second major outersurface defined by an outer surface of the layer of thermally conductiveor thermally capacitive material 14. In some embodiments, the heatcontrol member 10 includes an encapsulation member or layer surroundingall or part of the outer surface of the heat control member. In someembodiments, the layer of aerogel composition can be surrounded by anencapsulation member or layer surrounding all or part of the layer ofaerogel.

As illustrated in FIG. 7 , an exemplary heat control member 20 includesa first layer of reinforced aerogel composition 22 and a second layer ofreinforced aerogel composition 23. A layer of thermally conductive orthermally capacitive material 14 is disposed between the first layer ofreinforced aerogel composition 22 and the second layer of reinforcedaerogel composition 23. The heat control member 20 is substantiallyplanar and has a first major outer surface defined by an outer surfaceof the first layer of reinforced aerogel composition 22 and a secondmajor outer surface defined by an outer surface of the second layer ofreinforced aerogel composition 23. In some embodiments, the heat controlmember 10 includes an encapsulation member or layer surrounding all orpart of the outer surface of the heat control member. In someembodiments, the layer of aerogel composition can be surrounded by anencapsulation member or layer surrounding all or part of the layer ofaerogel.

As illustrated in FIG. 8 , an exemplary heat control member 30 includesa first layer of reinforced aerogel composition 32 and a second layer ofreinforced aerogel composition 33. The heat control member 30 issubstantially planar and has a first major outer surface defined by anouter surface of the first layer of reinforced aerogel composition 32and a second major outer surface defined by an outer surface of thesecond layer of reinforced aerogel composition 33. A layer of compliantmaterial 34 is disposed between the first and second layers of aerogelcomposition. A first layer of thermally conductive or thermallycapacitive material 36 is disposed between the first layer of reinforcedaerogel composition 32 and the layer of compliant material 34. A secondlayer of thermally conductive or thermally capacitive material 37 isdisposed between the second layer of reinforced aerogel composition 33and the layer of compliant material 34. In some embodiments, the heatcontrol member 30 includes an encapsulation member or layer surroundingall or part of the outer surface of the heat control member. In someembodiments, each layer of aerogel composition can be surrounded by anencapsulation member or layer surrounding all or part of the layer ofaerogel.

As illustrated in FIG. 9 , an exemplary heat control member 40 includesa first layer of reinforced aerogel composition 42 and a second layer ofreinforced aerogel composition 43. The heat control member 40 issubstantially planar and has a first major outer surface defined by anouter surface of the first layer of reinforced aerogel composition 42and a second major outer surface defined by an outer surface of thesecond layer of reinforced aerogel composition 43. A layer of compliantmaterial 44 is disposed between the first and second layers of aerogelcomposition. A first layer of thermally conductive or thermallycapacitive material 46 is disposed at a major outer surface of the firstlayer of reinforced aerogel composition 42. A second layer of thermallyconductive or thermally capacitive material 47 is disposed at a majorouter surface of the second layer of reinforced aerogel composition 43.In some embodiments, the heat control member 40 includes anencapsulation member or layer surrounding all or part of the outersurface of the heat control member. In some embodiments, each layer ofaerogel composition can be surrounded by an encapsulation member orlayer surrounding all or part of the layer of aerogel.

Production of multi-layer gel or aerogel compositions can include thefollowing steps: a) attaching a fluid-permeable facing layer to a sheetof reinforcement material to produce a laminated reinforcement sheet,wherein the facing layer contains pores or holes with diameters largeenough to allow fluids to diffuse through the facing material; b)infusing a gel precursor solution through the facing layer into thereinforcement sheet; and c) transitioning the gel precursor materialinto a gel material comprising a gel framework. A portion of the gelprecursor solution is likely to be retained within the pores or holes ofthe facing layer, such that the gel framework in the reinforcementmaterial of the base layer will extend into at least a portion of thefacing layer. The resulting product is a multi-layer gel compositioncomprising: a) at least one base layer comprising a reinforcementmaterial, and an gel framework integrated within the reinforcementmaterial; and b) at least one facing layer comprising a fluid-permeablefacing material, and an gel framework integrated within thefluid-permeable facing material; wherein at least a portion of the gelframework of the base layer extends into and is continuous with at leasta portion of the gel framework of the facing layer.

Large-scale production of multi-layer aerogel compositions can include aconveyor based system, wherein the production comprises the followingsteps: a) attaching at least one fluid-permeable facing layer to a sheetof reinforcement material to produce a laminated reinforcement sheet,wherein the facing layer contains pores or holes with diameters largeenough to allow fluids to diffuse through; and b) combining a gelprecursor solution with the laminated reinforcement sheet at one end ofa conveyor to produce a continuous reinforced gel sheet laminate;wherein at least a portion of the gel precursor solution infuses throughthe facing layer into the reinforcement sheet; and wherein the gelprecursor solution is combined with the laminated reinforcement sheet ata rate which allows the gel precursor solution to pass through thefacing layer and infiltrate the reinforcement sheet. In a preferredembodiment, the reinforcement material comprises an open-cell foamreinforcement material.

The reinforced, laminated gel sheet may be wound into a plurality oflayers (preferably around a mandrel with a uniform tension) andprocessed in subsequent chemical treatment, aging and drying steps. Anadditional separator layers can be co-wound between the gel sheet layersto facilitate aging or drying of the gel material, such as providing aflow path for aging agents or drying materials. In a preferredembodiment, the facing layer provides a flow path for aging agents ordrying materials, such that an additional separator layer is notrequired for aging and drying of the gel material.

Large-scale production of multi-layer aerogel compositions can include asemi-continuous, batch-based process which is commonly referred as agel-in-a-roll process, wherein the production comprises the followingsteps: a) attaching a fluid-permeable facing layer to a sheet ofreinforcement material, wherein the facing layer contains pores or holeswith diameters large enough to allow fluids to diffuse through; b)rolling the laminated reinforcement materials into plurality of layersas a preform roll; and c) combining a gel precursor solution with thepreform role. Additional separator layers may be co-rolled with thereinforcement material in the preform roll to provide a flow path forthe gel precursor solution, aging agents, and drying materials. In apreferred embodiment, the facing layer provides a flow path for the gelprecursor solution, aging agents, and drying materials, such that anadditional separator layer is not required. In a preferred embodiment,the reinforcement material comprises an open-cell foam reinforcementmaterial.

Aerogel compositions according to embodiments of the present disclosurecan be formed into various end products. In the simplest configuration,the reinforced aerogel composition can be in the form of a sheet. Thesheet can be formed continuously or semi-continuously, e.g., as a rolledproduct, or sheets of a desired size and shape can be cut or otherwiseformed from a larger sheet. The sheet material can be used to form athermal barrier between battery cells. In other configurations, thereinforced aerogel composition can be formed into a pouch, e.g., tocontain a pouch cell of a battery, or into a cylinder to containcylindrical battery cells.

Aerogel composites of the present disclosure may be shaped into a rangeof three-dimensional forms, including paneling, pipe preforms,half-shell preforms, elbows, joints, pouches, cylinders and other shapesregularly required in the application of insulation materials toindustrial and commercial applications. In one embodiment, thereinforcement material is formed into a desired shape prior to beinginfused with gel precursor material. The gel material is processed in amanner which allows the preform to maintain its shape, thus resulting ina reinforced aerogel preform of a desired shape. This technique offorming shaped aerogel preforms can be challenging and inefficientbecause of the difficulties required to process gel materials of variousshapes and configurations.

In exemplary embodiments of the present disclosure, aerogels can beformed from gel precursors or combinations of gel precursors whichcomprise at least one hydrophobic group. Such aerogels, e.g., inorganicaerogels such as silica-based aerogels, can include hydrophobic-boundsilicon. For example, the source of the hydrophobic-bound silicon in theaerogel can be the hydrophobic precursor material or materials. Inembodiments of the present disclosure, aerogels formed from suchprecursors can be hydrophobic. In some embodiments, aerogels formed fromsuch precursors can be intrinsically hydrophobic.

Within the context of the present disclosure, the term “intrinsicallyhydrophobic” refers to a material that possesses hydrophobicity withoutmodification by a hydrophobizing agent. For example, aerogels can betreated to impart or improve hydrophobicity. Hydrophobic treatment canbe applied to a sol-gel solution, a wet-gel prior to liquid phaseextraction, or to an aerogel subsequent to liquid phase extraction.Hydrophobic treatment can be carried out by reacting a hydroxy moiety ona gel, such as a silanol group (Si—OH) present on a framework of asilica gel, with a functional group of a hydrophobizing agent. Theresulting reaction converts the silanol group and the hydrophobizingagent into a hydrophobic group on the framework of the silica gel. Thehydrophobizing agent compound can react with hydroxyl groups on the gelaccording the following reaction: R_(N)MX₄._(N) (hydrophobizing agent) +MOH (silanol) → MOMR_(N) (hydrophobic group) + HX. Hydrophobic treatmentcan take place both on the outer macro-surface of a silica gel, as wellas on the inner-pore surfaces within the porous network of a gel.Published U.S. Pat. App. 2016/0096949 A1 (Paragraphs [0044] - [0048])teaches hydrophobic treatments and is hereby incorporated by referenceaccording to the individually cited paragraphs. However, as discussedabove, aerogels according to embodiments of the present disclosure arehydrophobic without hydrophobic treatment, e.g., without treatment by ahydrophobizing agent.

Production of an aerogel generally includes the following steps: i)formation of a sol-gel solution; ii) formation of a gel from the sol-gelsolution; and iii) extracting the solvent from the gel materials throughinnovative processing and extraction, to obtain a dried aerogelmaterial. This process is discussed below in greater detail,specifically in the context of forming inorganic aerogels such as silicaaerogels. However, the specific examples and illustrations providedherein are not intended to limit the present disclosure to any specifictype of aerogel and/or method of preparation. The present disclosure caninclude any aerogel formed by any associated method of preparation knownto those in the art, unless otherwise noted.

The first step in forming an inorganic aerogel is generally theformation of a sol-gel solution through hydrolysis and condensation ofsilica precursors, such as, but not limited to, metal alkoxideprecursors in an alcohol-based solvent. Major variables in the formationof inorganic aerogels include the type of alkoxide precursors includedin the sol-gel solution, the nature of the solvent, the processingtemperature and pH of the sol-gel solution (which may be altered byaddition of an acid or a base), and precursor/solvent/water ratio withinthe sol-gel solution. Control of these variables in forming a sol-gelsolution can permit control of the growth and aggregation of the gelframework during the subsequent transition of the gel material from the“sol” state to the “gel” state. While properties of the resultingaerogels are affected by the pH of the precursor solution and the molarratio of the reactants, any pH and any molar ratios that permit theformation of gels may be used in the present disclosure.

A sol-gel solution is formed by combining at least one gelling precursorwith a solvent. Suitable solvents for use in forming a sol-gel solutioninclude lower alcohols with 1 to 6 carbon atoms, particularly 2 to 4,although other solvents can be used as known to those with skill in theart. Examples of useful solvents include, but are not limited tomethanol, ethanol, isopropanol, ethyl acetate, ethyl acetoacetate,acetone, dichloromethane, tetrahydrofuran, and the like. Multiplesolvents can also be combined to achieve a desired level of dispersionor to optimize properties of the gel material. Selection of optimalsolvents for the sol-gel and gel formation steps thus depends on thespecific precursors, fillers, and additives being incorporated into thesol-gel solution; as well as the target processing conditions forgelling and liquid extraction, and the desired properties of the finalaerogel materials.

Water can also be present in the precursor-solvent solution. The wateracts to hydrolyze the metal alkoxide precursors into metal hydroxideprecursors. The hydrolysis reaction can be (using TEOS in ethanolsolvent as an example): Si(OC₂H₅)₄ + 4H₂O → Si(OH)₄ + 4(C₂H₅OH). Theresulting hydrolyzed metal hydroxide precursors remain suspended in thesolvent solution in a “sol” state, either as individual molecules or assmall polymerized (or oligomarized) colloidal clusters of molecules. Forexample, polymerization/condensation of the Si(OH)₄ precursors can occuras follows: 2 Si(OH)₄ = (OH)₃Si—O—Si(OH)₃ + H₂O. This polymerization cancontinue until colloidal clusters of polymerized (or oligomarized) SiO₂(silica) molecules are formed.

Acids and bases can be incorporated into the sol-gel solution to controlthe pH of the solution, and to catalyze the hydrolysis and condensationreactions of the precursor materials. While any acid may be used tocatalyze precursor reactions and to obtain a lower pH solution,exemplary acids include HC1, H₂SO₄, H₃PO₄, oxalic acid and acetic acid.Any base may likewise be used to catalyze precursor reactions and toobtain a higher pH solution, with an exemplary base comprising NH₄OH.

Strong bases may be used to catalyze precursor reactions and obtain ahigher pH solution. The use of a strong base to catalyze precursorreactions can enable the content of hydrophobic inorganic precursormaterials, e.g., MTES or DMDES, to be significantly higher than would bepossible using a weak base, e.g., a base comprising NH₄OH. Within thecontext of the present disclosure, the term “strong base” refers to bothinorganic and organic bases. For example, strong bases according toembodiments herein include cations selected from the group consisting oflithium, calcium, sodium, potassium, rubidium, barium, strontium, andguanidinium. For another example, the basic catalyst used to catalyzeprecursor reactions can include a catalytic amount of sodium hydroxide,lithium hydroxide, calcium hydroxide, potassium hydroxide, strontiumhydroxide, barium hydroxide, guanidine hydroxide, sodium hydroxide,tetrabutylammonium hydroxide, tetramethylammonium hydroxide, cholinehydroxide, phosphonium hydroxide, DABCO, DBU, guanidine derivatives,amidines, or phosphazenes.

The sol-gel solution can include additional co-gelling precursors, aswell as filler materials and other additives. Filler materials and otheradditives may be dispensed in the sol-gel solution at any point beforeor during the formation of a gel. Filler materials and other additivesmay also be incorporated into the gel material after gelation throughvarious techniques known to those in the art. In certain embodiments,the sol-gel solution comprising the gelling precursors, solvents,catalysts, water, filler materials, and other additives is a homogenoussolution that is capable of effective gel formation under suitableconditions.

Once a sol-gel solution has been formed and optimized, the gel-formingcomponents in the sol-gel can be transitioned into a gel material. Theprocess of transitioning gel-forming components into a gel materialcomprises an initial gel formation step wherein the gel solidifies up tothe gel point of the gel material. The gel point of a gel material maybe viewed as the point where the gelling solution exhibits resistance toflow and/or forms a substantially continuous polymeric frameworkthroughout its volume. A range of gel-forming techniques is known tothose in the art. Examples include, but are not limited to maintainingthe mixture in a quiescent state for a sufficient period of time;adjusting the pH of the solution; adjusting the temperature of thesolution; directing a form of energy onto the mixture (ultraviolet,visible, infrared, microwave, ultrasound, particle radiation,electromagnetic); or a combination thereof.

The process of transitioning gel-forming components (gel precursors)into a gel material may also include an aging step (also referred to ascuring) prior to liquid extraction or removal of the solvent from thegel (also referred to as drying of the gel). Aging a gel material afterit reaches its gel point can further strengthen the gel framework byincreasing the number of cross-linkages within the network. The durationof gel aging can be adjusted to control various properties within theresulting aerogel material. This aging procedure can be useful inpreventing potential volume loss and shrinkage during liquid extraction.Aging can involve maintaining the gel (prior to extraction) at aquiescent state for an extended period, maintaining the gel at elevatedtemperatures, adding cross-linkage promoting compounds, or anycombination thereof. Preferred temperatures for aging are typicallybetween about 10° C. and about 100° C., though other suitabletemperatures are contemplated herein as well. The aging of a gelmaterial typically continues up to the liquid extraction of the wet-gelmaterial.

The time period for transitioning gel-forming materials (gel precursors)into a gel material includes both the duration of the initial gelformation (from initiation of gelation up to the gel point), as well asthe duration of any subsequent curing and aging of the gel materialprior to liquid extraction or removal of the solvent from the gel (alsoreferred to as drying of the gel) (from the gel point up to theinitiation of liquid extraction/removal of solvent). The total timeperiod for transitioning gel-forming materials into a gel material istypically between about 1 minute and several days, typically about 30hours or less, about 24 hours or less, about 15 hours or less, about 10hours or less, about 6 hours or less, about 4 hours or less, about 2hours or less, and preferably, about 1 hour or less, about 30 minutes orless, about 15 minutes or less, or about 10 minutes or less.

In another embodiment, the resulting gel material may be washed in asuitable secondary solvent to replace the primary reaction solventpresent in the wet-gel. Such secondary solvents may be linear monohydricalcohols with one or more aliphatic carbon atoms, dihydric alcohols with2 or more carbon atoms, branched alcohols, cyclic alcohols, alicyclicalcohols, aromatic alcohols, polyhydric alcohols, ethers, ketones,cyclic ethers or their derivative. In another embodiment, the resultinggel material may be washed in additional quantities of the same solventpresent within the gel material, which among others, may remove anyundesired by-products or other precipitates in the gel material.

Once a gel material has been formed and processed, the liquid of the gelcan then be at least partially extracted from the wet-gel usingextraction methods, including innovative processing and extractiontechniques, to form an aerogel material. Liquid extraction, among otherfactors, plays an important role in engineering the characteristics ofaerogels, such as porosity and density, as well as related propertiessuch as thermal conductivity. Generally, aerogels are obtained when aliquid is extracted from a gel in a manner that causes low shrinkage tothe porous network and framework of the wet gel. This liquid extractionmay also be referred to as solvent removal or drying among others.

One example of an alternative method of forming a silica aerogel usesmetal oxide salts such as sodium silicate, also known as water glass. Awater glass solution is first produced by mixing sodium silicate withwater and an acid to form a silicic acid precursor solution. Saltby-products may be removed from the silicic acid precursor by ionexchange, surfactant separation, membrane filtration, or other chemicalor physical separation techniques. The resulting sol can then be gelled,such as by the addition of a base catalyst, to produce a hydrogel. Thehydrogel can be washed to remove any residual salts or reactants.Removing the water from the pores of the gel can then be performed viaexchange with a polar organic solvent such as ethanol, methanol, oracetone. The liquid in the gel is then at least partially extractedusing innovative processing and extraction techniques. In an embodiment,

Aerogels are commonly formed by removing the liquid mobile phase fromthe gel material at a temperature and pressure near or above thecritical point of the liquid mobile phase. Once the critical point isreached (near critical) or surpassed (supercritical) (i.e., pressure andtemperature of the system is at or higher than the critical pressure andcritical temperature respectively) a new supercritical phase appears inthe fluid that is distinct from the liquid or vapor phase. The solventcan then be removed without introducing a liquid-vapor interface,capillary pressure, or any associated mass transfer limitationstypically associated with liquid-vapor boundaries. Additionally, thesupercritical phase is more miscible with organic solvents in general,thus having the capacity for better extraction. Co-solvents and solventexchanges are also commonly used to optimize the supercritical fluiddrying process.

If evaporation or extraction occurs well below the critical point,capillary forces generated by liquid evaporation can cause shrinkage andpore collapse within the gel material. Maintaining the mobile phase nearor above the critical pressure and temperature during the solventextraction process reduces the negative effects of such capillaryforces. In certain embodiments of the present disclosure, the use ofnear-critical conditions just below the critical point of the solventsystem may allow production of aerogel materials or compositions withsufficiently low shrinkage, thus producing a commercially viableend-product.

Several additional aerogel extraction techniques are known in the art,including a range of different approaches in the use of supercriticalfluids in drying aerogels. For example, Kistler (J. Phys. Chem. (1932)36: 52-64) describes a simple supercritical extraction process where thegel solvent is maintained above its critical pressure and temperature,thereby reducing evaporative capillary forces and maintaining thestructural integrity of the gel network. U.S.

Pat. No. 4,610,863 describes an extraction process where the gel solventis exchanged with liquid carbon dioxide and subsequently extracted atconditions where carbon dioxide is in a supercritical state. U.S. Pat.No. 6670402 teaches extracting a liquid from a gel via rapid solventexchange by injecting supercritical (rather than liquid) carbon dioxideinto an extractor that has been pre-heated and pre-pressurized tosubstantially supercritical conditions or above, thereby producingaerogels. U.S. Pat. No. 5962539 describes a process for obtaining anaerogel from a polymeric material that is in the form a sol-gel in anorganic solvent, by exchanging the organic solvent for a fluid having acritical temperature below a temperature of polymer decomposition, andextracting the fluid/sol-gel using a supercritical fluid such assupercritical carbon dioxide, supercritical ethanol, or supercriticalhexane. U.S. Pat. No. 6315971 discloses a process for producing gelcompositions comprising drying a wet gel comprising gel solids and adrying agent to remove the drying agent under drying conditionssufficient to reduce shrinkage of the gel during drying. U.S. Pat. No.5420168 describes a process whereby Resorcinol/Formaldehyde aerogels canbe manufactured using a simple airdrying procedure. U.S. Pat. No.5565142 describes drying techniques in which the gel surface is modifiedto be stronger and more hydrophobic, such that the gel framework andpores can resist collapse during ambient drying or subcriticalextraction. Other examples of extracting a liquid from aerogel materialscan be found in U.S. Pat. Nos. 5275796 and 5395805. U.S. Pat.Publication No. 2019/0161909 provides examples of a process usingalkoxysilane and water glass to produce a high-density aerogel.

One embodiment of extracting a liquid from the wet-gel usessupercritical fluids such as carbon dioxide, including, for examplefirst substantially exchanging the primary solvent present in the porenetwork of the gel with liquid carbon dioxide; and then heating the wetgel (typically in an autoclave) beyond the critical temperature ofcarbon dioxide (about 31.06° C.) and increasing the pressure of thesystem to a pressure greater than the critical pressure of carbondioxide (about 1070 psig). The pressure around the gel material can beslightly fluctuated to facilitate removal of the liquid from the gel.Carbon dioxide can be recirculated through the extraction system tofacilitate the continual removal of the primary solvent from the wetgel. Finally, the temperature and pressure are slowly returned toambient conditions to produce a dry aerogel material. Carbon dioxide canalso be pre-processed into a supercritical state prior to being injectedinto an extraction chamber.

Another example of an alternative method of forming aerogels includesreducing the damaging capillary pressure forces at the solvent/poreinterface by chemical modification of the matrix materials in their wetgel state via conversion of surface hydroxyl groups to hydrophobictrimethylsilylethers, thereby allowing for liquid extraction from thegel materials at temperatures and pressures below the critical point ofthe solvent.

In yet another embodiment, liquid (solvent) in the gel material may befrozen at lower temperatures followed by a sublimation process wherebythe solvent is removed from the gel material. Such removal or drying ofthe solvent from the gel material is understood to be within the scopeof this disclosure. Such removal largely preserves the gel structure,thus producing an aerogel with unique properties.

Large-scale production of aerogel materials or compositions can becomplicated by difficulties related to the continuous formation of gelmaterials on a large scale; as well as the difficulties related toliquid extraction from gel materials in large volumes using innovativeprocessing and extraction techniques. In certain embodiments, aerogelmaterials or compositions of the present disclosure are accommodating toproduction on a large scale. In certain embodiments, gel materials ofthe present disclosure can be produced in large scale through acontinuous casting and gelation process. In certain embodiments, aerogelmaterials or compositions of the present disclosure are produced in alarge scale, requiring the use of large-scale extraction vessels. Largescale extraction vessels of the present disclosure can includeextraction vessels which have a volume of about 0.1 m³ or more, about0.25 m³ or more, about 0.5 m³ or more, or about 0.75 m³ or more.

Aerogel compositions of the present disclosure can have a thickness of15 mm or less, 10 mm or less, 5 mm or less, 4 mm or less, 3 mm or less,2 mm or less, 1 mm or less, 0.5 mm or less, 0.3 mm or less, or ranges ofthicknesses between any combination of the aforementioned thicknesses.

Aerogel compositions may be reinforced with various reinforcementmaterials to achieve a more flexible, resilient and conformablecomposite product The reinforcement materials can be added to the gelsat any point in the gelling process to produce a wet, reinforced gelcomposition. The wet gel composition may then be dried to produce areinforced aerogel composition.

Aerogel compositions may be OCMF-reinforced with various open-celledmacroporous framework reinforcement materials to achieve a moreflexible, resilient and conformable composite product. The OCMFreinforcement materials can be added to the gels at any point in thegelling process before gelation to produce a wet, reinforced gelcomposition. The wet gel composition may then be dried to produce anOCMF-reinforced aerogel composition. OCMF reinforcement materials can beformed from organic polymeric materials such as melamine or melaminederivatives, and are present in the form of a continuous sheet or panel.

Melamine OCMF materials can be produced from melamine-formaldehydeprecondensation solution. An aqueous solution of a melamine-formaldehydecondensation product is produced by combining a melamine-formaldehydeprecondensate with a solvent, an emulsifier/dispersant, a curing agentsuch as an acid, and a blowing agent such as a C5 to C7 hydrocarbon. Themelamine-formaldehyde solution or resin is then cured at elevatedtemperature above the boiling point of the blowing agent to produce anOCMF comprising a multiplicity of interconnected, three-dimensionallybranched melamine structures, with a corresponding network ofinterconnected pores integrated within the framework. Themelamine-formaldehyde precondensates generally have a molar ratio offormaldehyde to melamine in the range from 5:1 to 1.3:1 and typically inthe range from 3.5:1 to 1.5:1. The precondensates can be in the form ofa powder, a spray, a resin, or a solution. The solvent included in themelamine-formaldehyde precondensation solution can comprise alcoholssuch as methanol, ethanol, or butanol.

The emulsifier/dispersant included in the melamine-formaldehydeprecondensation solution can comprise an anionic surfactant, a cationicemulsifier, or a nonionic surfactant. Useful anionic surfactantsinclude, but are not limited to diphenylene oxide sulfonates, alkane-and alkylbenzenesulfonates, alkylnaphthalenesulfonates,olefinsulfonates, alkyl ether sulfonates, fatty alcohol sulfates, ethersulfates, α-sulfo fatty acid esters, acylaminoalkanesulfonates, acylisethionates, alkyl ether carboxylates, N-acylsarcosinates, alkyl, andalkylether phosphates. Useful cationic emulsifiers include, but are notlimited to alkyltriammonium salts, alkylbenzyl dimethylammonium salts,or alkylpyridinium salts. Useful nonionic surfactants include, but arenot limited to alkylphenol polyglycol ethers, fatty alcohol polyglycolethers, fatty acid polyglycol ethers, fatty acid alkanolamides, ethyleneoxide-propylene oxide block copolymers, amine oxides, glycerol fattyacid esters, sorbitan esters, and alkylpolyglycosides. Theemulsifier/dispersant can be added in amounts from 0.2% to 5% by weight,based on the melamine-formaldehyde precondensate.

The curing agent included in the melamine-formaldehyde precondensationsolution can comprise acidic compounds. The amount of these curatives isgenerally in the range from 0.01% to 20% by weight and typically in therange from 0.05% to 5% by weight, all based on the melamine-formaldehydeprecondensate. Useful acidic compounds include, but are not limited toorganic and inorganic acids, for example selected from the groupconsisting of hydrochloric acid, sulfuric acid, phosphoric acid, nitricacid, formic acid, acetic acid, oxalic acid, toluenesulfonic acids,amidosulfonic acids, acid anhydrides, and mixtures thereof.

The blowing agent included in the melamine-formaldehyde precondensationsolution can comprise physical blowing agents or chemical blowingagents. Useful physical blowing agents include, but are not limited tohydrocarbons, such as pentane and hexane; halogenated hydrocarbons, moreparticularly chlorinated and/or fluorinated hydrocarbons, for examplemethylene chloride, chloroform, trichloroethane, chlorofluorocarbons,and hydro-chlorofluorocarbons (HCFCs); alcohols, for example methanol,ethanol, n-propanol or isopropanol, ethers, ketones and esters, forexample methyl formate, ethyl formate, methyl acetate or ethyl acetate;and gases, such as air, nitrogen or carbon dioxide. In certainembodiments, it is preferable to add a physical blowing agent having aboiling point between 0° C. and 80° C. Useful chemical blowing agentsinclude, but are not limited to, isocyanates mixed with water (releasingcarbon dioxide as active blowing agent); carbonates and/or bicarbonatesmixed with acids (releasing carbon dioxide as active blowing agent); andazo compounds, for example azodicarbonamide. The blowing agent ispresent in the melamine-formaldehyde precondensation solution in anamount of 0.5% to 60% by weight, particularly 1% to 40% by weight and incertain embodiments 1.5% to 30%by weight, based on themelamine-formaldehyde precondensate.

The melamine-formaldehyde precondensation solution can be formed into amelamine OCMF material by heating the solution to a temperaturegenerally above the boiling point of the blowing agent used, therebyforming an OCMF comprising a multiplicity of interconnected,three-dimensionally branched melamine structures, with a correspondingnetwork of interconnected open-cell pores integrated within theframework. The introduction of heat energy may be effected viaelectromagnetic radiation, for example via high-frequency radiation at 5to 400 kW, for example 5 to 200 kW and in certain embodiments 9 to 120kW per kilogram of the mixture used in a frequency range from 0.2 to 100GHz, or more specifically 0.5 to 10 GHz. Magnetrons are a useful sourceof dielectric radiation, and one magnetron can be used or two or moremagnetrons at the same time.

The OCMF material can be dried to remove residual liquids (water,solvent, blowing agent) from the OCMF material. An after-treatment canalso be utilized to hydrophobicize the OCMF material. Thisafter-treatment can employ hydrophobic coating agents having highthermal stability and/or low flammability, for example silicones,siliconates or fluorinated compounds.

The density of the melamine OCMF is generally in the range from 0.005 to0.3 g/cc, for example in the range from 0.01 to 0.2 g/cc, in certainembodiments in the range from 0.03 to 0.15 g/cc, or most specifically inthe range from 0.05 to 0.15 g/cc. The average pore diameter of themelamine OCMF is generally in the range of 10 µm to about 1000 µm,particularly in the range from 50 to 700 µm.

In an embodiment, OCMF reinforcement materials are incorporated into theaerogel composition as continuous sheet. The process comprises initiallyproducing a continuous sheet of OCMF-reinforced gel by casting orimpregnating a gel precursor solution into a continuous sheet of OCMFreinforcement material, and allowing the material to form into areinforced gel composite sheet. The liquid may then be at leastpartially extracted from the OCMF-reinforced gel composite sheet toproduce a sheet-like, OCMF-reinforced aerogel composition.

Aerogel compositions can include an opacifier to reduce the radiativecomponent of heat transfer. At any point prior to gel formation,opacifying compounds or precursors thereof may be dispersed into themixture comprising gel precursors. Examples of opacifying compoundsinclude, but are not limited to Boron Carbide (B₄C), Diatomite,Manganese ferrite, MnO, NiO, SnO, Ag₂O, Bi₂O₃, carbon black, graphite,titanium oxide, iron titanium oxide, aluminum oxide, zirconium silicate,zirconium oxide, iron (II) oxide, iron (III) oxide, manganese dioxide,iron titanium oxide (ilmenite), chromium oxide, carbides (such as SiC,TiC or WC), or mixtures thereof. Examples of opacifying compoundprecursors include, but are not limited to TiOSO₄ or TiOCl₂. In someembodiments, the opacifying compounds used as additives can excludewhiskers or fibers of silicon carbide. When aerogel compositions areintended for use in electrical devices, e.g., in batteries as a barrierlayer or other related applications, the composition including anopacifier can desirably possess a high dielectric strength with highvolume and surface resistivities. In such embodiments, carbon additivesused as an opacifier can be non-conductive or modified to reduceelectrical conductivity. For example, the opacifier can be surfaceoxidized to reduce electrical conductivity. In some embodiments,carbonaceous additives with inherent electrical conductivity can be usedas an opacifier in aerogel compositions intended for used in electricaldevices. In such embodiments, the conductive carbonaceous additives canbe used at concentrations below the percolation threshold so as toprovide a composition with a suitable dielectric strength for use in anelectrical device.

Aerogel compositions can include one or more fire-class additives.Within the context of the present disclosure, the term “fire-classadditive” refers to a material that has an endothermic effect in thecontext of reaction to fire and can be incorporated into an aerogelcomposition. Furthermore, in certain embodiments, fire-class additiveshave an onset of endothermic decomposition (E_(D)) that is no more than100° C. greater than the onset of thermal decomposition (T_(d)) of theaerogel composition in which the fire-class additive is present, and incertain embodiments, also an E_(D) that is no more than 50° C. lowerthan the T_(d) of the aerogel composition in which the fire-classadditive is present. In other words, the E_(D) of fire-class additiveshas a range of (T_(d) - 50° C.) to (T_(d) + 100° C.);

$E_{D}\left\{ \begin{matrix}{max:\mspace{6mu} T_{d} + 100\mspace{6mu}{^\circ}\text{C}} \\{min:\mspace{6mu} T_{d} - 50\mspace{6mu}{^\circ}\text{C}}\end{matrix} \right)$

Prior to, concurrent with, or even subsequent to incorporation or mixingwith the sol (e.g., silica sol prepared from alkyl silicates or waterglass in various ways as understood in prior art), fire-class additivescan be mixed with or otherwise dispersed into a medium including ethanoland optionally up to 10% vol. water. The mixture may be mixed and/oragitated as necessary to achieve a substantially uniform dispersion ofadditives in the medium. Without being bound by theory, utilizing ahydrated form of the above-referenced clays and other fire-classadditives provides an additional endothermic effect. For example,halloysite clay (commercially available under the tradename DRAGONITEfrom Applied Minerals, Inc. or from Imerys simply as Halloysite),kaolinite clay are aluminum silicate clays that in hydrated form has anendothermic effect by releasing water of hydration at elevatedtemperatures (gas dilution). As another example, carbonates in hydratedform can release carbon dioxide on heating or at elevated temperatures.

Within the context of the present disclosure, the terms “heat ofdehydration” means the amount of heat required to vaporize the water(and dihydroxylation, if applicable) from the material that is inhydrated form when not exposed to elevated temperatures. Heat ofdehydration is typically expressed on a unit weight basis.

In certain embodiments, fire-class additives of the present disclosurehave an onset of thermal decomposition of about 100° C. or more, about130° C. or more, about 200° C. or more, about 230° C. or more, about240° C. or more, about 330° C. or more, 350° C. or more, about 400° C.or more, about 415° C. or more, about 425° C. or more, about 450° C. ormore, about 500° C. or more, about 550° C. or more, about 600° C. ormore, about 650° C. or more, about 700° C. or more, about 750° C. ormore, about 800° C. or more, or in a range between any two of thesevalues. In certain embodiments, fire-class additives of the presentdisclosure have an onset of thermal decomposition of about 440° C. or570° C. In certain embodiments, fire-class additives of the presentdisclosure have an onset of thermal decomposition which is no more than50° C. more or less than the T_(d) of the aerogel composition (withoutthe fire-class additive) into which the fire-class additive isincorporated, no more than 40° C. more or less, no more than 30° C. moreor less, no more than 20° C. more or less, no more than 10° C. more orless, no more than 5° C. more or less, or in a range between any two ofthese values

The fire-class additives of this disclosure include, clay materials suchas, but not limited to, phyllosilicate clays (such as illite), kaolin orkaolinite (aluminum silicate; Al₂Si₂O₅(OH)₄), metakaolin, halloysite(aluminum silicate; Al₂Si₂O₅(OH)4), endellite (aluminum silicate;Al₂Si₂O₅(OH)₄), mica (silica minerals), diaspore (aluminum oxidehydroxide; α-AlO(OH)), gibbsite (aluminum hydroxide), boehmite (aluminumoxide hydroxide; γ-AlO(OH)), montmorillonite, beidellite, pyrophyllite(aluminum silicate; Al₂Si₄O₁₀(OH)₂), nontronite, bravaisite, smectite,leverrierite, rectorite, celadonite, attapulgite, chloropal,volkonskoite, allophane, racewinite, dillnite, severite, miloschite,collyrite, cimolite and newtonite, sodium bicarbonate (NaHCO₃),magnesium hydroxide (or magnesium dihydroxide, “MDH”), aluminatrihydrate (“ATH”), gypsum (calcium sulfate dihydrate; CaSO₄·2H₂O),barringtonite (MgCO₃·2 H₂O), nesquehonite (MgCO_(3·)3 H₂O), lansfordite(MgCO₃·5 H₂O), hydromagnesite (hydrated magnesium carbonate;Mg₅(CO₃)₄(OH)₂·4H₂O), other carbonates such as, but not limited to,dolomite and lithium carbonate. Among the clay materials, certainembodiments of the present disclosure use clay materials that have atleast a partial layered structure. In certain embodiments of the presentdisclosure, clay materials as fire-class additives in the aerogelcompositions have at least some water such as in hydrated form. Theadditives may be in hydrated crystalline form or may become hydrated inthe manufacturing/processing of the compositions of the presentdisclosure. In certain embodiments, fire-class additives also includelow melting additives that absorb heat without a change in chemicalcomposition. An example of this class is a low melting glass, such asinert glass beads. Other additives that may be useful in thecompositions of the present disclosure include, but are not limited to,wollastonite (calcium silicate) and titanium dioxide (TiO₂). In certainembodiments, other additives may include infrared opacifiers such as,but not limited to, titanium dioxide or silicon carbide, ceramifierssuch as, but not limited to, low melting glass frit, calcium silicate orcharformers such as, but not limited to, phosphates and sulfates. Incertain embodiments, additives may require special processingconsiderations such as techniques to ensure the additives are uniformlydistributed and not agglomerated heavily to cause product performancevariations. The processing techniques may involve additional static anddynamic mixers, stabilizers, adjustment of process conditions and othersknown in the art.

The amount of additives in the aerogel compositions disclosed herein maydepend on the desired properties of the composition. The amount ofadditives used during preparation and processing of the sol gelcompositions is typically referred to as a weight percentage relative tosilica content of the sol. The amount of additives in the sol may varyfrom about 5 wt% to about 70 wt% by weight relative to silica content.In certain embodiments, the amount of additives in the sol is between 10wt% and 60 wt% relative to silica content and in certain preferredembodiments, it is between 20 wt% and 40 wt% relative to silica content.In exemplary embodiments, the amount of additives in the sol relative tosilica content is in the range of about 5% to about 20%, about 10% toabout 20%, about 10% to about 30%, about 10% to about 20%, about 30 wt%to about 50 wt%, about 35 wt% to about 45 wt%, or about 35 wt% to about40 wt% relative to silica content. In some embodiments, the amount ofadditives in the sol is at least about 10 wt% relative to silica contentor about 10 wt% relative to silica content. In some embodiments, theamount of additives is in the range of about 5 wt% to about 15 wt%relative to silica content. In certain embodiments, the additives may beof more than one type. One or more fire-class additives may also bepresent in the final aerogel compositions. In some preferred embodimentswhich include aluminum silicate fire-class additives, the additives arepresent in the aerogel compositions in about 60-70 wt% relative tosilica content. For example, in some preferred embodiments which includealuminum silicate fire-class additives such as kaolin or combinations ofaluminum silicate fire-class additives such as kaolin with aluminatrihydrate (“ATH”), the total amount of additives present in the aerogelcompositions is about 30-40 wt% relative to silica content. For anotherexample, in some preferred embodiments in which additives includesilicon carbide, the total amount of additives present in the aerogelcompositions is about 30-40 wt%, e.g. 35 wt%, relative to silicacontent. For another example, in some preferred embodiments in whichadditives include silicon carbide, the total amount of additives presentin the aerogel compositions is about 5-15 wt%, e.g. 10 wt%, relative tosilica content.

When referring to the final reinforced aerogel compositions, the amountof additives is typically referred to as a weight percentage of thefinal reinforced aerogel composition. The amount of additives in thefinal reinforced aerogel composition may vary from about 1% to about50%, about 1% to about 25%, or about 10% to about 25% by weight of thereinforced aerogel composition. In exemplary embodiments, the amount ofadditives in the final reinforced aerogel composition is in the range ofabout 10% to about 20% by weight of the reinforced aerogel composition.In exemplary embodiments, the amount of additives in the finalreinforced aerogel composition as a weight percentage of the compositionis about 1%, about 2% about 3%, about 4%, about 5%, about 6%, about 7%,about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about14%, about 15%, about 16%, about 17%, about 18%, about 19% about 20% orin a range between any of the aforementioned percentages. In certainembodiments, the amount of additives in the final reinforced aerogelcomposition is about 15% by weight of the reinforced aerogelcomposition. In certain embodiments, the amount of additives in thefinal reinforced aerogel composition is about 13% by weight of thereinforced aerogel composition. For example, in some preferredembodiments which include additives such as silicon carbide, the totalamount of additives present in the aerogel compositions is about 10-20%,e.g., about 15%, by weight of the reinforced aerogel composition. Foranother example, in some preferred embodiments in which additivesinclude silicon carbide, the total amount of additives present in theaerogel compositions is about 3-5%, e.g., about 4%, by weight of thereinforced aerogel composition.

In certain embodiments, fire-class additives can be classified orgrouped based on their onset temperature of thermal decomposition. Forexample, fire-class additives can be classified or grouped as having anonset temperature of thermal decomposition less than about 200° C., lessthan about 400° C., or greater than about 400° C. For example, additiveshaving an onset temperature of thermal decomposition less than about200° C. include sodium bicarbonate (NaHCO₃), nesquehonite (MgCO₃·3 H₂O),and gypsum (calcium sulfate dihydrate; CaSO₄·2H₂O). For another example,additives having an onset temperature of thermal decomposition less thanabout 400° C. include alumina trihydrate (“ATH”), hydromagnesite(hydrated magnesium carbonate; Mgs(CO₃)₄(OH)₂·4H₂O), and magnesiumhydroxide (or magnesium dihydroxide, “MDH”). For another example,additives having an onset temperature of thermal decomposition less thanabout 400° C. include halloysite (aluminum silicate; Al₂Si₂O₅(OH)₄),kaolin or kaolinite (aluminum silicate; Al₂Si₂O₅(OH)₄), boehmite(aluminum oxide hydroxide, γ-AlO(OH)) or high temperature phase changematerials (PCM).

In certain embodiments of the present disclosure, clay materials e.g.,aluminosilicate clays such as halloysite or kaolinite, as additives inthe aerogel compositions are in the dehydrated form, e.g.,meta-halloysite or metakaolin. Other additives that may be useful in thecompositions of the present disclosure include, but are not limited to,wollastonite (calcium silicate) and titanium dioxide (TiO2). In certainembodiments, other additives may include infrared opacifiers such as,but not limited to, titanium dioxide or silicon carbide, ceramifierssuch as, but not limited to, low melting glass frit, calcium silicate orcharformers such as, but not limited to, phosphates and sulfates. Incertain embodiments, additives may require special processingconsiderations such as techniques to ensure the additives are uniformlydistributed and not agglomerated heavily to cause product performancevariations. The processing techniques may involve additional static anddynamic mixers, stabilizers, adjustment of process conditions and othersknown in the art. One or more fire-class additives may also be presentin the final aerogel compositions.

In certain embodiments, the inclusion of additives, e.g.,aluminosilicate clay-based materials such as halloysite or kaolin, inthe aerogel materials and compositions of the present disclosure canprovide improved high temperature shrinkage properties. An exemplarytest method for high temperature shrinkage is “Standard Test Method forLinear Shrinkage of Preformed High-Temperature Thermal InsulationSubjected to Soaking Heat” (ASTM C356, ASTM International, WestConshohocken, PA). In such tests, referred to as a “thermal soak,”materials are exposed to temperatures greater than 1000° C. for aduration of up to 60 minutes. In certain exemplary embodiments, aerogelmaterials or compositions of the present disclosure can have hightemperature shrinkage, i.e., a linear shrinkage, width shrinkage,thickness shrinkage or any combination of dimensional shrinkage, ofabout 20% or less, about 15% or less, about 10% or less, about 6% orless, about 5% or less, 4% or less, 3% or less, 2% or less, 1% or less,or in a range between any two of these values.

In some exemplary embodiments, certain basic catalysts used to catalyzeprecursor reactions can result in trace levels of alkali metals in theaerogel composition. Trace levels, e.g., 100 to 500 ppm, of alkali,e.g., sodium or potassium, in the aerogel materials can have adeleterious effect on high temperature shrinkage and thermal durability.However, without being bound by any particular mechanism or theory,aluminosilicate clay-based materials such as halloysite or kaolin cansequester fugitive alkali, e.g., sodium or potassium, thereby reducingor eliminating the effect of akali on shrinkage and thermal durability.In certain embodiments of the present disclosure, the aluminosilicateclay materials are in the dehydrated form, e.g., meta-halloysite ormetakaolin. For example, aerogel materials or compositions including anamount of metakaolin or meta-halloysite of greater than about 0.5 wt%relative to silica content can significantly reduce thermal shrinkageand thermal durability. In exemplary embodiments, aerogel materials orcompositions can include an amount of metakaolin or meta-halloysite in arange of about 0.5 wt% to about 3.0 wt% relative to silica content.

FIG. 1 illustrates test data for samples of heat control membermaterials according to embodiments disclosed herein in which atemperature of 650° C. was applied to one surface of a heat controlmember, i.e., the hot side, and the temperature at the other side of theheat control member, i.e., the cold side, was measured over time. Thecontrol sample corresponds to the composition of Example 1, described inmore detail below. Samples A, B and C are embodiments of heat controlmembers disclosed herein including kaolin as an additive. Sample Acorresponds to the composition of Example 2, described in more detailbelow. Sample B corresponds to the composition of Example 4, below.Sample C corresponds to the composition of Example 3 below. As shown inFIG. 1 ,the compositions including kaolin provide a time to reach atemperature of 75° C. at the cold face of about 30 seconds, a time toreach a temperature of 120° C. at the cold face of about 1 minute, atime to reach a temperature of 150° C. at the cold face of about 90seconds, and at time to reach a temperature of 180° C. at the cold faceof about 4 minutes. The unusually good performance with kaolin mineralsas additives at temperature ranges below 200° C. was surprising andunexpected.

In certain embodiments of the present disclosure, methods are providedto prepare reinforced aerogel compositions with fire-class performance.The fire-class compositions of these embodiments also possesshydrophobicity sufficient for use as thermal insulation in industrialenvironments, as measured by water uptake and low thermal conductivityto help meet the ever-demanding energy conservation needs. To obtainthese combinations of desirable properties, simply loading additives oreven fire-class additives are not successful. While one can try variouspermutations and combinations or various additives and arrive at anoptimized solution, such efforts are not always successful and presentrisks for a viable manufacturing with repeatable quality control onthese desired properties. An important aspect of these embodiments is toassess the thermal behavior (assessed through thermogravimetry ordifferential scanning calorimetry) of the composition that wouldotherwise provide all desirable properties except for the fireperformance and consider a fire-class additive that closely matches theonset of thermal decomposition of the underlying composition oralternatively, the temperature at which most heat is emitted with thefire-class additives’ onset of thermal decomposition or the temperatureat which most heat is absorbed.

In certain embodiments, the desired fire properties of the finalcomposition may include not just the inherent property such as heat ofcombustion (ISO 1716), but also system fire properties such as reactionto fire performance as per ISO 1182. In the case of ISO 1182, weightloss, increase in furnace temperature, and flame time are assessed whenexposed to a furnace at a temperature of about 750° C.

A fiber or OCMF reinforced aerogel composition may have variouscomponents that add oxidizable organic content (fuel) to the system.Additionally, it may have various other components, while notcontributing as fuel, may interfere in combustion upon exposure to fire.As such, combustion behavior of such systems cannot be predicted simplybased on the constituent elements. In situations where a multitude ofproperties are desired, in certain embodiments, the composition shouldbe arrived at without regard to its fire property and such arrivedcomposition’s thermal performance should be assessed to find a suitablefire-class additive that will provide the fire property withoutcompromising the other properties the starting composition was intendedto provide.

In certain embodiments, onset of thermal decomposition is a criticalproperty of the composition. In certain other embodiments, thetemperature at which the peak heat release may be a critical propertyfor the purposes of developing an enhanced fire-performing aerogelcompositions. When multiple fuel components are present in thecomposition identified by multiple peaks in the DSC curve, suchcompositions are well served by matching the temperature of the peakheat release of the reinforced aerogel composition with a fire-classadditive having a temperature of endothermic peak heat release within140° C., 120° C., 100° C. or 80° C. In many embodiments, the temperatureof endothermic peak heat release is within 50° C.

The aerogel materials and compositions of the present disclosure havebeen shown to be highly effective as insulation materials. However,application of the methods and materials of the present disclosure arenot intended to be limited to applications related to insulation. Themethods and materials of the present disclosure can be applied to anysystem or application, which would benefit from the unique combinationof properties or procedures provided by the materials and methods of thepresent disclosure.

EXAMPLES

The following examples provide various non-limiting embodiments andproperties of the present disclosure. In the examples below, theadditive wt% is provided with 100% reference being the total weight ofthe aerogel composition. FIGS. 1 and 2 are charts showing heat controlmembers of the examples below controlling time-to-temperature behavior.

Example 1

A glass fiber reinforced silica aerogel composition was producedaccording to the methods disclosed above. The reinforced silica aerogelcomposition had a thickness of about 3 mm and included 21.7 wt% ofsynthetic amorphous silica, 12.2 wt% methylsilylated silica, 62.27 wt%fibrous glass, and 3.8 wt% iron oxide (Fe₂O₃). An 8 inch square sampleof this composition was evaluated using a hot surface performance testwith the hot surface at 650° C. The temperature at the cold face of thesample composition was measured over a period of time. For the samplecomposition of this example, the time to reach a temperature of 75° C.at the cold face was about 15 seconds, the time to reach a temperatureof 120° C. at the cold face was about 30 seconds, the time to reach atemperature of 150° C. at the cold face was about 40 seconds, and thetime to reach a temperature of 180° C. at the cold face was about 1minute. Data for the sample composition of this example corresponds to“Control” in the chart of FIG. 1 .

Example 2

A glass fiber reinforced silica aerogel composition was producedaccording to the methods disclosed above. The reinforced silica aerogelcomposition had a thickness of about 3 mm and included 15.3 wt% ofsynthetic amorphous silica, 8.6 wt% methylsilylated silica, 37.8 wt%fibrous glass, and 38.3 wt% kaolin. The target silica density was 0.07g/cc. An 8 inch square sample of this composition was evaluated using ahot surface performance test with the hot surface at 650° C. Thetemperature at the cold face of the sample composition was measured overa period of time. For the sample composition of this example, the timeto reach a temperature of 75° C. at the cold face was about 32 seconds,the time to reach a temperature of 120° C. at the cold face was about 1minute, the time to reach a temperature of 150° C. at the cold face wasabout 90 seconds, and the time to reach a temperature of 180° C. at thecold face was about 4 minutes. Data for the sample composition of thisexample corresponds to “A” in the chart of FIG. 1 .

Example 3

A glass fiber reinforced silica aerogel composition was producedaccording to the methods disclosed above. The reinforced silica aerogelcomposition had a thickness of about 3 mm and included 15.3 wt% ofsynthetic amorphous silica, 8.6 wt% methylsilylated silica, 37.8 wt%fibrous glass, and 38.3 wt% kaolin. The target silica density was 0.09g/cc. An 8 inch square sample of this composition was evaluated using ahot surface performance test with the hot surface at 650° C. Thetemperature at the cold face of the sample composition was measured overa period of time. For the sample composition of this example, the timeto reach a temperature of 75° C. at the cold face was about 38 seconds,the time to reach a temperature of 120° C. at the cold face was about 68seconds, the time to reach a temperature of 150° C. at the cold face wasabout 102 seconds, and the time to reach a temperature of 180° C. at thecold face was about 4 minutes. Data for the sample composition of thisexample corresponds to “C” in the chart of FIG. 1 .

Example 4

A glass fiber reinforced silica aerogel composition was producedaccording to the methods disclosed above. The reinforced silica aerogelcomposition had a thickness of about 3 mm and included 15.3 wt% ofsynthetic amorphous silica, 8.6 wt% methylsilylated silica, 37.8 wt%fibrous glass, and 38.3 wt% of a combination of kaolin and ATH. Thetarget silica density was 0.07 g/cc. An 8 inch square sample of thiscomposition was evaluated using a hot surface performance test with thehot surface at 650° C. The temperature at the cold face of the samplecomposition was measured over a period of time. For the samplecomposition of this example, the time to reach a temperature of 75° C.at the cold face was about 36 seconds, the time to reach a temperatureof 120° C. at the cold face was about 1 minute, the time to reach atemperature of 150° C. at the cold face was about 96 seconds, and thetime to reach a temperature of 180° C. at the cold face was about 3minutes and 21 seconds. Data for the sample composition of this examplecorresponds to “B” in the chart of FIG. 1 .

Example 5

A glass fiber reinforced silica aerogel composition was producedaccording to the methods disclosed above. The reinforced silica aerogelcomposition had a thickness of about 3.5 mm and included 21.7 wt% ofsynthetic amorphous silica, 12.2 wt% methylsilylated silica, 62.27 wt%fibrous glass, and 3.8 wt% iron oxide (Fe₂O₃). An 8 inch square sampleof this composition was evaluated using a hot surface performance testwith the hot surface at 650° C. The temperature at the cold face of thesample composition was measured over a period of time. For the samplecomposition of this example, the time to reach a temperature of 75° C.at the cold face was about 13 seconds, the time to reach a temperatureof 120° C. at the cold face was about 22 seconds, the time to reach atemperature of 150° C. at the cold face was about 29 seconds, and thetime to reach a temperature of 180° C. at the cold face was about 36seconds. Data for the sample composition of this example corresponds to“Control” in the chart of FIG. 2 .

Example 6

Sols of both methyltriethoxysilane (MTES) and tetraethoxylsilane (TEOS)or polyethylsilicate (Silbond 40) were individually prepared viahydrolysis under acidic conditions in ethanol. The ratio andconcentration of sol materials were adjusted to obtain a hydrophobecontent from MTES of about 36 wt% and to obtain aerogels with about 8.0wt% organic content within the aerogel material. Silicon carbide (SiC)was incorporated into the combined sol at a weight percentage of atleast 35 wt% relative to silica content. The combined sol was thenstirred for no less than 1 hour.

Guanidine hydroxide (2 M) was added to the combined sol at concentrationsufficient to target aerogel density of about 0.07-0.085 g/cc. Thecatalyzed sol containing SiC was cast into a fiber reinforcing phase andallowed to gel. Just prior to and immediately after gelation, the fiberreinforced wet gel was subject to a series of molding steps using aheavy weight stainless steel roller. Repeated rolling of the wet gel wasconducted for no greater than four times and at a controlled thicknessof 3.0 mm using rigid incompressible gauge blocks positioned at theedges of the wet gel. After curing for no greater than 1 h at roomtemperature, the aerogel materials were aged for about 12 h at 68° C. inethanol aging fluid at an approximate fluid:gel ratio of 3:1. The agedgel was subjected to solvent extraction with supercritical CO₂, and thendried for 2 h at 110° C.

The fiber reinforcing phase was a homogeneous non-woven materialcomprised of textile grade glass fibers (E-glass composition), about 5.6mm thick with a density of about 250 g/m². The resulting reinforcedsilica aerogel composition was about 2.5 mm thick and was about 44%aerogel (comprising about 28% of synthetic amorphous silica and about16% methylsilylated silica), 41% fibrous glass, and 15% silicon carbideby weight of the reinforced silica aerogel composition, resulting in anexpected material density of about 0.20 g/cc (given a 0.085 g/cc aerogeldensity).

An 8 inch square sample of this composition was evaluated using a hotsurface performance test with the hot surface at 650° C. The temperatureat the cold face of the sample composition was measured over a period oftime. For the sample composition of this example, the time to reach atemperature of 75° C. at the cold face was about 13 seconds, the time toreach a temperature of 120° C. at the cold face was about 24 seconds,the time to reach a temperature of 150° C. at the cold face was about 31seconds, and the time to reach a temperature of 180° C. at the cold facewas about 42 seconds. Data for the sample composition of this examplecorresponds to “E” in the chart of FIG. 2 .

Example 7

Sols of both methyltriethoxysilane (MTES) and tetraethoxylsilane (TEOS)or polyethylsilicate (Silbond 40) were individually prepared viahydrolysis under acidic conditions in ethanol. The ratio andconcentration of sol materials were adjusted to obtain a hydrophobecontent from MTES of about 36 wt% and to obtain aerogels with about 8.0wt% organic content within the aerogel material. Silicon carbide (SiC)was incorporated into the combined sol at a weight percentage of atleast 35 wt% relative to silica content. The combined sol was thenstirred for no less than 1 hour.

Guanidine hydroxide (2 M) was added to the combined sol at concentrationsufficient to target aerogel density of about 0.07-0.085 g/cc. Thecatalyzed sol containing SiC was cast into a fiber reinforcing phase andallowed to gel. Just prior to and immediately after gelation, the fiberreinforced wet gel was subject to a series of molding steps using aheavy weight stainless steel roller. Repeated rolling of the wet gel wasconducted for no greater than four times and at a controlled thicknessof 2.0 mm using rigid incompressible gauge blocks positioned at theedges of the wet gel. After curing for no greater than 1 h at roomtemperature, the aerogel materials were aged for about 12 h at 68° C. inethanol aging fluid at an approximate fluid:gel ratio of 3:1. The agedgel was subjected to solvent extraction with supercritical CO2, and thendried for 2 h at 110° C.

The fiber reinforcing phase was a homogeneous non-woven materialcomprised of textile grade glass fibers (E-glass composition), about 5.6mm thick with a density of about 250 g/m². The resulting reinforcedsilica aerogel composition about 2.0 mm thick and was about 36% aerogel(comprising about 23% of synthetic amorphous silica and about 13%methylsilylated silica), 51% fiber and 13% silicon carbide by weight ofthe reinforced silica aerogel composition, resulting in an expectedmaterial density of about 0.20 g/cc (given a 0.085 g/cc aerogeldensity).

An 8 inch square sample of this composition was evaluated using a hotsurface performance test with the hot surface at 650° C. The temperatureat the cold face of the sample composition was measured over a period oftime. For the sample composition of this example, the time to reach atemperature of 75° C. at the cold face was about 11 seconds, the time toreach a temperature of 120° C. at the cold face was about 21 seconds,the time to reach a temperature of 150° C. at the cold face was about 31seconds, and the time to reach a temperature of 180° C. at the cold facewas about 39 seconds. Data for the sample composition of this examplecorresponds to “D” in the chart of FIG. 2 .

A sample of this composition was evaluated in compression. Deformationof the sample was measured to provide a stress-strain relationship forthe sample. Data for this analysis is shown in FIG. 3 .

Example 8

Sols of both methyltriethoxysilane (MTES) and tetraethoxylsilane (TEOS)or polyethylsilicate (Silbond 40) were individually prepared viahydrolysis under acidic conditions in ethanol. The ratio andconcentration of sol materials were adjusted to obtain a hydrophobecontent from MTES of about 36 wt% and to obtain aerogels with about 8.0wt% organic content within the aerogel material. Silicon carbide (SiC)was incorporated into the combined sol at a weight percentage of atleast about 10 wt% relative to silica content. The combined sol was thenstirred for no less than 1 hour.

Guanidine hydroxide (2 M) was added to the combined sol at concentrationsufficient to target aerogel density of about 0.07-0.085 g/cc. Thecatalyzed sol containing SiC was cast into a fiber reinforcing phase andallowed to gel. Just prior to and immediately after gelation, the fiberreinforced wet gel was subject to a series of molding steps using aheavy weight stainless steel roller. Repeated rolling of the wet gel wasconducted for no greater than four times and at a controlled thicknessof 3.0 mm using rigid incompressible gauge blocks positioned at theedges of the wet gel. After curing for no greater than 1 h at roomtemperature, the aerogel materials were aged for about 12 h at 68° C. inethanol aging fluid at an approximate fluid:gel ratio of 3:1. The agedgel was subjected to solvent extraction with supercritical CO₂, and thendried for 2 h at 110° C.

The fiber reinforcing phase was a homogeneous non-woven materialcomprised of textile grade glass fibers (E-glass composition), about 4mm thick with a density of about 225 g/m². The resulting reinforcedsilica aerogel composition was about 2.25 mm thick and was about 39%aerogel (comprising about 25% of synthetic amorphous silica and about14% methylsilylated silica), 57% fibrous glass, and 4% silicon carbideby weight of the reinforced silica aerogel composition, resulting in anexpected material density of about 0.16 g/cc (given a 0.075 g/cc aerogeldensity).

An 8 inch square sample of this composition was evaluated using a hotsurface performance test with the hot surface at 650° C. The temperatureat the cold face of the sample composition was measured over a period oftime. For the sample composition of this example, the time to reach atemperature of 75° C. at the cold face was about 9 seconds, the time toreach a temperature of 120° C. at the cold face was about 19 seconds,the time to reach a temperature of 150° C. at the cold face was about 25seconds, and the time to reach a temperature of 180° C. at the cold facewas about 34 seconds. Data for the sample composition of this example isshown in the chart of FIG. 4 .

The advantages set forth above, and those made apparent from theforegoing description, are efficiently attained. Since certain changesmay be made in the above construction without departing from the scopeof the invention, it is intended that all matters contained in theforegoing description or shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention that, as amatter of language, might be said to fall therebetween.

1. A battery module comprising: a first battery cell and a secondbattery cell; a heat control member between the first battery cell andthe second battery cell, the heat control member comprising; multiplelayers of reinforced aerogel, including; a first layer of reinforcedaerogel; a second layer of reinforced aerogel; and a thermallyconductive material layer between the first layer of reinforced aerogeland the second layer of reinforced aerogel.
 2. The battery module ofclaim 1, wherein the lofty aerogel composition provides compressibilityof at least 50% of an uncompressed thickness.
 3. The battery module ofclaim 1, wherein the lofty aerogel composition provides compressibilityof at least 80% of an uncompressed thickness.
 4. The battery module ofclaim 1, wherein the lofty aerogel composition provides resilientrecovery to at least 70% of an uncompressed thickness after compression.5. The battery module of claim 1, wherein the lofty aerogel compositionprovides resilient recovery to at least 80% of an uncompressed thicknessafter compression.
 6. The battery module of claim 1, wherein the loftyaerogel composition provides a thermal conductivity at 10° C. of about40 mW/mK or less while under compression.
 7. The battery module of claim1, wherein the first layer of reinforced aerogel includes a differentresilience than the second layer of reinforced aerogel.
 8. The batterymodule of claim 1, wherein the thermally conductive material layerincludes metallic foil.
 9. The battery module of claim 1, wherein thethermally conductive material layer includes carbon.
 10. The batterymodule of claim 1, wherein the first layer of reinforced aerogel and thesecond layer of reinforced aerogel further include a reinforcement fibercomprising oxidized polyacrylonitrile (OPAN).
 11. The battery module ofclaim 1, wherein the first layer of reinforced aerogel and the secondlayer of reinforced aerogel further include a reinforcement fibercomprising glass fiber.
 12. The battery module of claim 1, wherein thethermally conductive material layer forms a direct interface with boththe first layer of reinforced aerogel and the second layer of reinforcedaerogel.
 13. A battery module comprising: a first battery cell and asecond battery cell; a heat control member comprising: multiple layersof reinforced aerogel between the first battery cell and the secondbattery cell, the multiple layers of reinforced aerogel including; afirst layer of reinforced aerogel; a second layer of reinforced aerogel;and a thermally conductive material layer between the first layer ofreinforced aerogel and the second layer of reinforced aerogel; whereinone or more of the multiple layers of reinforced aerogel include aporous structure to provide resilience.
 14. The battery module of claim13, wherein the porous structure includes macropores.
 15. The batterymodule of claim 14, wherein the porous structure includes mesopores. 16.The battery module of claim 13, wherein the reinforced aerogel includingthe porous structure provides compressibility of at least 50% of anuncompressed thickness.
 17. The battery module of claim 13, wherein thereinforced aerogel including the porous structure provides a thermalconductivity at 10° C. of about 40 mW/mK or less while undercompression.
 18. A battery module comprising: a first battery cell and asecond battery cell; a heat control member comprising: multiple layersof fiber reinforced aerogel between the first battery cell and thesecond battery cell, the multiple layers of reinforced aerogelincluding; a first layer of reinforced aerogel; a second layer ofreinforced aerogel; and a thermally conductive material layer betweenthe first layer of reinforced aerogel and the second layer of reinforcedaerogel; wherein one or more of the multiple layers of reinforcedaerogel include a resilient reinforcing material.
 19. The battery moduleof claim 18, wherein the resilient reinforcing material includes poreswith both open cell portions and closed cell portions.
 20. The batterymodule of claim 19, wherein the pores in the resilient reinforcingmaterial include macropores.
 21. The battery module of claim 19, whereinthe pores in the resilient reinforcing material include mesopores.